geometry

[cindy]

what is the total surface area of a triangular prism with a length of 60cm, width of 60cm, and a height of 40cm HELLLLLLLLLLLLLLLLLLLP PLEASE

 

[cindy]

GEOMETRY

I also need to know the total surface area of a cylinder with a radius of 8ft and height of 24 ft. Also, the surface area for a cone with a radius of 9 in, length of 13.5 in and height of 10 in. Thanks for any help anybody can give me. I am totally stumped. Thanks so much :?

 

[ting]

Draw a sketch of the prism, write in all the side lengths. You should see what you need to do.

You need to find the total surface area of the three rectangular faces (l*w). You will need to divide the end triangular face into 2 right triangles and use pythagoras' theorem to find the width of two the rectangular face. Unless you spot the pythagorean triple.

And the area of the two triangular faces, (1/2*b*h).

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Think of a cylinder as a rolled rectangle. The height of the cylinder is the length of the rectangle and the circumference is the width of the rectangle.

Plus the two circular ends.

So you will need these two formulae for circles

c = 2*pi*r

A = pi*r^2