Height of Cone

[richiesmasher]

Hi I tried to attach an image but it never works for me.



I have figured out part (a) and part (B)(i)

Now I am on part B(ii): And it states to find the height.

I know that the circumference of the base is 44cm.

I know the radius of the base is 7 cm.

So I got help from someone and I saw that if you draw an actual cone the segment here forms a right angled triangle, of which would be the height.

I then thought I had this solved as the radius 7 cm, w²ould be the base of the triangle, and the bigger radius 10.5 cm would be the hypotenuse.

But my book says 12.6 cm is the answer for the height.

I get something else after using Pythagorean theorem.

I get 7.8cm.

 

[Dr.Peterson]

I then thought I had this solved as the radius 7 cm, would be the base of the triangle, and the bigger radius 10.5 cm would be the hypotenuse.

But my book says 12.6 cm is the answer for the height.

I get something else after using Pythagorean theorem.

I get 7.8cm.

I get your answer.

I think they accidentally added instead of subtracting in their work. They should know that the height must be less than the hypotenuse, 10.5!

So they made a silly mistake. Answers in books aren't always checked as well as they should be.