Question

what is the height of a right cone when the radius is 5cm

Answer 1

So that is the cross-section of the cone. What do you notice?

Answer 2

i cut the cone in half using a right triangle?

Answer 3

Well it is a triangle. That means you can use TOA SOH CAH and Pythagoras's theorem to get what you want.

Also, by right cone they mean a cone that goes straight up like this: instead of

Answer 4

so it will always be 90 degrees ? so what ever equals 90?

Answer 5

The angle between it's height and base will always be 90 degrees, yes. What do you mean what ever equals 90?

Answer 6

90 degrees, so the hypotenuses is 90 degrees?

Answer 7

Hypotenuse is the length of the longest side or side that is opposite to the right angle. Its value can not be in degrees. How well do you know trigonometry?

Answer 8

i dont! im learning it in class and my teacher doesnt explain things well me and a few other girls are very confused and he gives us alot of home work to do and its all on the computer, im not sure how to figure this question out.
the actual question is, a pyramid has a surface area of 260 cm2
the right cone has a radius of 5cm. the cone and the pyramid have equal surface area. what is the height of the cone

Answer 9

@Pleiades37 Would you check your text and see if "what is the height of the cone" states exactly that or if the problem states "what is the slant height of the cone?" There's a difference between the two.

Answer 10

it only gives me the once number, the radius being 5cm. thats all i have to work with..

Answer 11

That is not what I am asking.

I think I can help you solve this but I need to see the ENTIRE question as it appears in your text.

Begin a question with ALL of the question.

Answer 12

I am asking if this ---> what is the height of the cone is what appears in your text?

Also, is this a multiple choice question?

Answer 13

Before I work on this problem, I need to see ALL of the problem, every word of it. Okay?

Answer 14

The surface area of a cone has the formula:

SA = π * r² + π * r * L where r is the radius of the base of the cone and L is the SLANT height of the cone.

Answer 15

The surface area of the pyramid is equal to the surface area of the cone.

So, 260 = π * 5² + π * 5 * L

The task is to solve the above equation for L. ---> Give that a try @Pleiades37

Answer 16

ok, thank you so much for your help i will give that a try for sure!!!

Answer 17

@Pleiades37 When you solve for L, it will not be the height of the cone.

L should be approximately 11.552.

Then, you have to take a look at a cone and use the Pythagorean Theorem to get the height of the cone.

Answer 18

Take a look at the equation to solve to find the height of the cone.

@Pleiades37