Math Is Fun Forum

owenflo

Member

Registered: 2014-07-21

Posts: 115

PLEASE HELP fast

1. If a hexagon has a side of 3 units, what is the area of the hexagon?

3^2 x 6/4 x tan (180/6)

54/4 x tan (180/6)

54/2.3094

23.38

2. If a hexagon has an area of 100 units, what is the length of one side?

100=3sqrt3/2 x s^2|s=side

s^2=100/3sqrt3/2

s^2=100/2.598076

s^2=38.490021

s=6.204032

3. If a hexagon has a radius (center to point of angle) of 6, what is the side of the hexagon?

answer is 6.

4. If a hexagon has a radius (center to point of angle) of 6, what is the area of the hexagon?

r^2 sqrt3/4

6^2 sqrt 3/4

36 x sqrt3/4

36 x .433021

15.588756

a=6 x 15.588756

93.53

5. If a hexagon is resting on a flat side, and has a total height of 18, what is the length of each side of the hexagon?

A=9^2 x 6 * tan x (180/6)

A=280.59

3 (sqrt3/2) x s^2 = 280.59

s^2= 280.59 x 2/3 x sqrt3

s^2= 561.18/5.196152

s^2=107.99

s=10.39

6. If a hexagon is resting on a flat side, and has a total height of 18, what is the area of the hexagon?

A=9^2 x 6 * tan x (180/6)

A=280.59

7. Problem solver (worth 4 points): Come up with a way to find the area and volume of a football. Include in your answer a way to acquire any necessary measurements without cutting or otherwise destroying the football. Also include all necessary formulas to implement your idea. (You don't need to find actual numbers, just outline the method in step by step detail--think of all the measurements you'll need to acquire and how you'll get them.)

r=circumference/(2pi)

A=4pir^2

V=4pi x r^3/3

MY TEACHER SAID

As I advised on August 28, these problems need to be solved with tools that you have learned in this course.  Those tools include the Pythagorean Theorem, the properties of special right triangles, or basic trigonometry ratios.

PLEASE HELP ME TO FIX

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: PLEASE HELP fast

Hi;

For #7 you can first look here:

http://www.mathisfunforum.com/viewtopic … 83#p242283

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

owenflo

Member

Registered: 2014-07-21

Posts: 115

Re: PLEASE HELP fast

Okay, still need help

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: PLEASE HELP fast

Hi;

For 1) My calculation is 23.38268590217984, so which would you pick?

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,140

Re: PLEASE HELP fast

hi owenflo

The first three answers are correct.

As I advised on August 28, these problems need to be solved with tools that you have learned in this course.  Those tools include the Pythagorean Theorem, the properties of special right triangles, or basic trigonometry ratios.

You haven't said what tools you have been taught so it is very hard to say what you should be doing.

Here is a diagram which may help. 

A REGULAR hexagon can be divided into 6 equilateral triangles. 

Each of those can be split in two, to make a right angled triangle with angles 30-60-90.

The area of a triangle is half the base x the height.  The key to these problems is that height.  It can be calculated using trig., like this

You can also use Pythag like this:

Hope that helps,

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

owenflo

Member

Registered: 2014-07-21

Posts: 115

Re: PLEASE HELP fast

She wants to know more about the formulas and why i have chosen them.... please help have been on this lesson forever really need to move on.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,140

Re: PLEASE HELP fast

What was wrong with the formulas I suggested ?

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

owenflo

Member

Registered: 2014-07-21

Posts: 115

Re: PLEASE HELP fast

She said I can use simpler tools... she said she can tell im getting the formulas from somewhere. i dont know what 'tools' to use

Bob

Administrator

Registered: 2010-06-20

Posts: 10,140

Re: PLEASE HELP fast

hi owenflo,

In Q1 you wrote:

3^2 x 6/4 x tan (180/6)

This does lead to the right answer but she cannot understand how you got this calculation (and neither can I).  Why did you do this calculation ? Rather than using the simple formulas you have been taught ?  That is why she is unhappy with your answers.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

owenflo

Member

Registered: 2014-07-21

Posts: 115

Re: PLEASE HELP fast

Please help me use a simpler formula

Bob

Administrator

Registered: 2010-06-20

Posts: 10,140

Re: PLEASE HELP fast

hi owenflo,

I thought I had done that in post 5.

Let's start at the beginning.  What formulas have you been taught in this topic ?

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

owenflo

Member

Registered: 2014-07-21

Posts: 115

Re: PLEASE HELP fast

Triangle Area Theorem
The area A of any triangle is equal to one-half the product of any base b and corresponding height h.
Formula: A = (1/2)bh

Trapezoid Area Theorem
The area A of any trapezoid is equal to one-half the product of the height h and the sum of the bases, b1 and b2.
Formula: A = (1/2)h(b1 + b2)

Area=Base * Height /2

Sphere Area Theorem
The area A of any sphere with radius r is equal to 4(PI) times the square of the radius
Area Formula: A = 4(PI)r^2

Cylinder Area Theorem
For any right circular cylinder with radius r and height h, the total area T is two times the area of the base plus the lateral area.
Formula: T = 2(PI)rh + 2(PI)r^2

Cylinder Volume Theorem
The volume V of any cylinder with radius r and height h is equal to the product of the area of a base and the height.
Formula: V = (PI)(r^2)h

L = Ph

Right Prism Volume Postulate
The volume V of any right prism is the product of B (the area of the base) and the height h of the prism.
Volume Formula: V = Bh

owenflo

Member

Registered: 2014-07-21

Posts: 115

Re: PLEASE HELP fast

That is all the formulas I know

owenflo

Member

Registered: 2014-07-21

Posts: 115

Re: PLEASE HELP fast

For just the lessons 20-21

Bob

Administrator

Registered: 2010-06-20

Posts: 10,140

Re: PLEASE HELP fast

You also need some formulas from trigonometry or at least Pythagoras theorem.  I'll show you using both.

Let's say you are asked for the area of a regular hexagon with each side = 14 cm.

As the hexagon is regular the internal angles are all 120 and if you join opposite points you will divide the hexagon into 6 equilateral triangles.

If one triangle is split in half the resulting 'half' triangles are 30-60-90

Let's concentrate on that triangle (shown in yellow).

The hypotenuse is 14 cm.  The shortest side is 7 cm.  There are three ways to calculate the third side (which will be the height of the triangle).  You can pick the method you like best.

I'm using H for the hypotenuse, A for the adjacent and O for the opposite.

Method (1) Pythagoras theorem.

Method (2) Using cosines.

Method (3) using tangents.

Then we can work out the area of the yellow triangle (using half base x height).

and so the area of the whole hexagon is 12 times this

I hope this helps you to do the questions.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

owenflo

Member

Registered: 2014-07-21

Posts: 115

Re: PLEASE HELP fast

1. If a hexagon has a side of 3 units, what is the area of the hexagon?

2. If a hexagon has an area of 100 units, what is the length of one side?

3. If a hexagon has a radius (center to point of angle) of 6, what is the side of the hexagon?

4. If a hexagon has a radius (center to point of angle) of 6, what is the area of the hexagon?

5. If a hexagon is resting on a flat side, and has a total height of 18, what is the length of each side of the hexagon?

6. If a hexagon is resting on a flat side, and has a total height of 18, what is the area of the hexagon?

7. Problem solver (worth 4 points): Come up with a way to find the area and volume of a football. Include in your answer a way to acquire any necessary measurements without cutting or otherwise destroying the football. Also include all necessary formulas to implement your idea. (You don't need to find actual numbers, just outline the method in step by step detail--think of all the measurements you'll need to acquire and how you'll get them.)

Bob

Administrator

Registered: 2010-06-20

Posts: 10,140

Re: PLEASE HELP fast

hi owenflo,

I thought you wanted to get this completed quickly.  Why have you posted the questions again?

If you post your revised answers using the correct formulas, I'll be happy to check them for you. 

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

owenflo

Member

Registered: 2014-07-21

Posts: 115

Re: PLEASE HELP fast

I don't know how to do it.... I am having so much trouble. Going blank

Bob

Administrator

Registered: 2010-06-20

Posts: 10,140

Re: PLEASE HELP fast

I hoped that post 15 would be enough.  Sorry you cannot repeat it.  Maybe someone else on the forum can help.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

owenflo

Member

Registered: 2014-07-21

Posts: 115

Re: PLEASE HELP fast

I just don't know what number 1 is.. Can someone get me started so maybe I can catch on

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: PLEASE HELP fast

Bob's first drawing in post #15 did not help? Where are you stuck?

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

owenflo

Member

Registered: 2014-07-21

Posts: 115

Re: PLEASE HELP fast

For #1 I got 23.38
for #2 I got 6.2

owenflo

Member

Registered: 2014-07-21

Posts: 115

Re: PLEASE HELP fast

#3
The radius is equal to the side length so that means that the side length is 6

#5
is 9 because half is equal to the side lengths

#4
93.530

#6
210.44

No idea on #7

Bob

Administrator

Registered: 2010-06-20

Posts: 10,140

Re: PLEASE HELP fast

hi owenflo,

You had those answers back in post 1 (except for Q6 ... I think your post 1 answer is right not your post 23 answer)  You haven't said anything about Q5 but that doesn't matter as post 1 was correct for this too.

But your teacher wanted to know what formulas you were using and you still haven't told us what you intend to send in as your complete answer.  She obviously wants to see your working.  If you want your working to be checked here first, you must post it.

Q7.  In post 12 you listed the formulas you had learnt.  The volume of a sphere wasn't in the list so here it is:

You already know that the surface area depends on the radius.

So if you assume the football is a soccer ball it will be roughly a sphere, so you can make use of these formulas.

But you need to know the radius.  If you've got a ruler there are lots of ways to estimate this.  All you have to do is describe a method and then say what calculations you would use to get the area and volume.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

owenflo

Member

Registered: 2014-07-21

Posts: 115

Re: PLEASE HELP fast

#1

3sqrt 3x^2/2 = 23.3826859

#2

a= 3 1/4 sqrt 2 a/9 = 6.2

#3

Radius is equal to side length so that means that the side length is 6.

#4

Help

#5

3 sqrt 36^2/2 = 9

#6

3 sqrt 3 9^2/2= 210.4441731