Question

The total surface area of a cylinder with height 5 cm is 88 sq cm.Find its radius

Answer 1

Answer:

Step-by-step explanation:

  total surface area = 2πr (r +h) = 88

                    88 = 2 x 22/7 x r (r + h)              

                    88 = 2 * 22/7 * r (r + 5)                  

                     88 * 7 = 44 * r ( r +5)                    

                   (88*7)/44 = r (r+5)

                 2 * 7 = r ( r + 5 )

              14 = r^{2} + 5r

            0 = r^{2} + 5r- 14

            0= r^{2} -2r+7r-14

          r (r-2) + 7 (r-2) = 0

                (r-2) (r+7) = 0

                  r = 2, r= -7

the radius of cylinder is r = 2 cm