Hey everyone, Got this question which shouldn't be troubling me but I can't get my head around it:
"Here is the net of a cone
The net is a sector of a circle, centre 'O', and radius 15 cm. Reflex angle AOB = 216 degrees. The net makes a cone of slant height 15 cm.
Work out the vertical height of the cone."
I hope that's clear enough for everyone, sorry about the quality (tried to do it quickly in paint). I've got an idea of the formulas to use, but I'm going to keep my mouth shut to see how close I was to the proper answer.