SOLUTION: A cone has a slant height of 9cm and curved surface 65πcm^2 find: (a) The base radius of the cone (b) The perpendicular height of the cone (c) The vertical angle of the cone t

Algebra ->  Surface-area -> SOLUTION: A cone has a slant height of 9cm and curved surface 65πcm^2 find: (a) The base radius of the cone (b) The perpendicular height of the cone (c) The vertical angle of the cone t      Log On


   

Question 1183365: A cone has a slant height of 9cm and curved surface 65πcm^2 find:
(a) The base radius of the cone
(b) The perpendicular height of the cone (c) The vertical angle of the cone to the nearest degree
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
.

pi * r * l = 65 pi ( r = radius, l = slant height)

r = 65 *pi/pi*l
r= 65/l = 65/9 = 7.22 cm
h+=+sqrt%28l%5E2-h%5E2%29
h+=sqrt%289%5E2-7.22%5E2%29
h=5.37 cm
tan a = 7.22/5.37
tan a = 1.34
a = cotan 1.34
a=53.2 deg
angle of cone = 2*(53.2) deg