Posted by Angelita Marie on .
Find the radius of a right cone with slant height 21 m and surface area 168pi m2

Algebra 
drwls,
Does that surface area include the base?
The area of the conical portion is
A = pi* R * (slant height)
You can use that formula to solve for the radius, R
See http://www.uwm.edu/~ericskey/TANOTES/Geometry/node15.html