Math Is Fun Forum

h3691218

Member

Registered: 2019-08-24

Posts: 5

Geometry: Need some help working out the following-

1. Find the surface area and the volume of the figure below. Break your work down into three sections: Cone, Cylinder, and Sphere. Show the work for both the surface area and volume. Then find the total surface area and volume. Use 3.14 for π. R

      Um, someone explain?

2.   Construct a prism from the above regular hexagon.  The height of the hexagonal prism is 5 feet. Find the surface area and the volume of this prism.

     Not too confident about this one either.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,640

Re: Geometry: Need some help working out the following-

hi h3691218

Welcome to the forum.

You've not given us any diagrams or measurements so it's hard to be more helpful.  Have a look at these pages and post again if you're still stuck.

https://www.mathsisfun.com/geometry/con … inder.html

That site has a good search facility so you can find prims too.

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

h3691218

Member

Registered: 2019-08-24

Posts: 5

Re: Geometry: Need some help working out the following-

1. Find the surface area and the volume of the figure below. Break your work down into three sections: Cone, Cylinder, and Sphere. Show the work for both the surface area and volume. Then find the total surface area and volume. Use 3.14 for π. R

     img-2-L24_N6.jpg

2.   Construct a prism from the above regular hexagon.  The height of the hexagonal prism is 5 feet. Find the surface area and the volume of this prism.
 
      Measurements from my last problem: 360/6=60 degrees, 180-60=120/2= Side angle of 60. Tan(60)=h/8/2=4, 4*tan(60)=6.928 for the height. A= 1/2(8)(6.928), A= 27.712. Entire Area= 27.712(6)= 166.3 sq ft.

h3691218

Member

Registered: 2019-08-24

Posts: 5

Re: Geometry: Need some help working out the following-

https://imgur.com/DOrPIFc 

Don't know if the last link worked?

h3691218

Member

Registered: 2019-08-24

Posts: 5

Re: Geometry: Need some help working out the following-

WAIT! sorry, that was the wrong image link, here's the right one:

     https://imgur.com/JnunUwZ

Bob

Administrator

Registered: 2010-06-20

Posts: 10,640

Re: Geometry: Need some help working out the following-

hi h3691218

Thanks.  I've got the image of the cone/cylinder/hemisphere and I can show you how to calculate that.  I'm not getting the other image. 

Here's the formulas you need:

cone: 

h is given as 8; the radius is the same for all three parts: 10/2 = 5

s is the length of the sloping edge.  You'll have to use Pythagoras for that:

cylinder:

h' is what's left after you've taken off 8 and 5 from 25.

hemisphere:

If you had been asked for the surface area of each part then you'd need to include the base(s) but, as they are joined, this shouldn't be needed.

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

h3691218

Member

Registered: 2019-08-24

Posts: 5

Re: Geometry: Need some help working out the following-

Then how would you find the total surface area and volume?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,640

Re: Geometry: Need some help working out the following-

You need two answers; one for surface area and one for volume.  For each, just add up the three component answers to get the totals.

Bob

ps.  If you post what you have worked out, I'll check them for you.

---

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

JunPark

Member

Registered: 2020-06-30

Posts: 4

Re: Geometry: Need some help working out the following-

would this be correct

5 times 168 = 840
V = 840 ft ^ 3
8 times 5 = 40
40 times 6 = 240
168 times 2 + 240 = 576
Sa = 576 sqft ^2