SOLUTION: the height of a cylinder measures 4 cm more than its radius. find the height of the cylinder if its total area is 140pi?
Algebra ->
Human-and-algebraic-language
-> SOLUTION: the height of a cylinder measures 4 cm more than its radius. find the height of the cylinder if its total area is 140pi?
Log On
Question 610383: the height of a cylinder measures 4 cm more than its radius. find the height of the cylinder if its total area is 140pi? Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! the height of a cylinder measures 4 cm more than its radius. find the height of the cylinder if its total area is 140pi?
---
Total surface area = 2(pi)r^2 + 2(pi)r*h
Solve:
140 = 2(pi)r^2 + 2(pi)*r(r+4)
70 = (pi)r^2 + (pi)(r^2+4r)
70 = 2(pi)r^2 + 4(pi)r
35 = (pi)r^2 + 2(pi)r
Rearrange:
(pi)r^2 + 2(pi)r - 35 = 0
r = 2.484 cm
h = 6.484 cm
====================
Cheers,
Stan H.
===================================
(