I have read other posts and im still confused!

malaysiawill · 2016-05-29 06:00:58

1. If a hexagon has a side of 3 units, what is the area of the hexagon?
A= 23.38
2. If a hexagon has an area of 100 units, what is the length of one side?
S= 6.20
3. If a hexagon has a radius (center to point of angle) of 6, what is the side of the hexagon?
S=6
4. If a hexagon has a side length of 6, what is the area of the hexagon?
A= 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?
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= 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.) *I need help with this one*

bobbym · 2016-05-29 06:33:03

Hi;

Does the area of a hexagon formula help?

Where s is the length of one side. Now just plug in:

Can you finish from here? Hint: use a calculator.

malaysiawill · 2016-05-29 06:51:27

That does not help with 7 but it helps with 1 through 6.

bobbym · 2016-05-29 11:30:44

I solved this problem once before:

http://www.mathisfunforum.com/viewtopic … =20153&p=2

Post #48 and beyond.

malaysiawill · 2016-06-01 02:47:04

I read that post 2-3 times and I'm still confused. I got the volume is 4/3(pi)*ab^2, but I'm not sure what the area is?

Bob · 2016-06-01 02:49:40

hi

If you can stay on line now I'll try to help

Bob

oh dear ... you have logged out already.

Last edited by Bob (2016-06-01 02:52:48)

malaysiawill · 2016-06-01 03:02:38

sorry I'm on, thank you for helping me

Bob · 2016-06-01 03:05:12

Is it question 7 you want help with?

B

malaysiawill · 2016-06-01 03:05:50

yes its question 7 I want help with.

Bob · 2016-06-01 03:13:31

and we're using a funny shaped ball not a UK soccer ball? That's round.

I think you're only expected to think of a sensible method ... it doesn't have to use advanced formulas ... especially if you have no idea where they come from.

For a volume I'd put the ball in a large tub with some water in and see how much the water goes up. If you can calculate that using formulas you do know that should be acceptable. So start with a cylindrical tub and measure its radius. Put in enough water to totally submerge the ball. Before you put the ball in mark where the water level is. Then push in the ball and mark again where the water is. Calculate the gain the height of the water ... use the volume of a cylinder formula to calculate the volume of water displaced ... that must equal the volume of the ball.

I'll post this whilst thinking about the area.

Bob

malaysiawill · 2016-06-01 03:15:24

okay, thank you.

Bob · 2016-06-01 03:29:05

You could imagine that the ball is sliced up into a series of disks along its major axis. Each disk has a radius which you'd have to measure and a thickness. The area of one disk would be the curved surface area of a cylinder which I think you know. Do each calculation and add them up.

This won't be wonderfully accurate ** but you can say that, and add that to improve the accuracy, I would take more but thinner disks. This is a method that is used to get the area of tricky to measure shapes.

Bob

** Because the strange shape means these aren't exactly disks.

Or you could get some squared paper and cut it up into squares (say 1 cm or 1 inch square) Then stick these all over the ball trying to cover as much area as possible. Where you have smaller uncovered bits, cut the squares in half to cover those bits .......

Sorry I've got to go now but I'll look in again later in case you want more help.

malaysiawill · 2016-06-01 03:32:14

I don't need to find numbers. so the area would be A=(pi)r^2?

Bob · 2016-06-01 06:34:00

I've included a diagram:

Along the x axis slice solid into sections. Approximate each section to be a cylinder. The red line indicates the radius of one slice shaded orange. The 'height' (thickness)of a cylinder would depend on how far apart you make the slices. Let's say the radius of a slice is 'r' and the thickness 't'.

The area of the curved surface of the slice is 2.pi.r.t (think of a marrow; you peel of the surface making a strip 't' wide and circumference long.)

You'd have to make a separate calculation for every slice as the radii will vary.

The slices aren't really cylinders so the calculation is only approximate. If you have lots more slices by making 't' smaller, the calculation becomes more accurate.

I think the point of this question is just to get you thinking about how you can use what you already know to calculate tricky shaped solids.

Bob

Math Is Fun Forum

#1 2016-05-29 06:00:58

I have read other posts and im still confused!

#2 2016-05-29 06:33:03

Re: I have read other posts and im still confused!

#3 2016-05-29 06:51:27

Re: I have read other posts and im still confused!

#4 2016-05-29 11:30:44

Re: I have read other posts and im still confused!

#5 2016-06-01 02:47:04

Re: I have read other posts and im still confused!

#6 2016-06-01 02:49:40

Re: I have read other posts and im still confused!

#7 2016-06-01 03:02:38

Re: I have read other posts and im still confused!

#8 2016-06-01 03:05:12

Re: I have read other posts and im still confused!

#9 2016-06-01 03:05:50

Re: I have read other posts and im still confused!

#10 2016-06-01 03:13:31

Re: I have read other posts and im still confused!

#11 2016-06-01 03:15:24

Re: I have read other posts and im still confused!

#12 2016-06-01 03:29:05

Re: I have read other posts and im still confused!

#13 2016-06-01 03:32:14

Re: I have read other posts and im still confused!

#14 2016-06-01 06:34:00

Re: I have read other posts and im still confused!

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