what is the radius?

Question

A can of beans has surface area

368368

cmsquared2.

Its height is

1212

cm. What is the radius of the circular​ top? (Hint: The surface area consists of the circular top and bottom and a rectangle that represents the side cut open vertically and​ unrolled.)

Answer 1

Surface Area of cylinder is. 2πr² + 2πrh. which is the two lids cut out and the side split and stretched flat.

then 368,368 = 2πr² + 2πrh. dividing out the 2π will make the problem easier.

368368/2π = r² + 1212r. then put everything on the right side and use the quadratic formula.

Answer 2

surface area = 2* pi*r*h + 2*pi*r^2

368 = 2* pi * r * 12 + 2* pi * r^2

184 = 12*pi * r + pi * r^2

pi*r^2 + 12*pi*r - 184 = 0

r^2 + 12*r - 184/pi = 0

r = [-12 +or- sqrt ( 144 + 4*184/pi)]/ 2

negative branch results in negative measures

The APPROXIMATE RADIUS is 3.72466+