Question

a cylinder has a diameter of a 20 cm and height is 7 cm explain whether tripling the height would have the same effect of the surface area as doubling the radius or not​

Answer 1

Surface Area will be different in both cases.

Step-by-step explanation:

Given,Diameter = 20 cm or Radius = 10 cm

         Height = 7 cm

We know that,Surface Area= 2πrh

Case 1:

If height is tripled,Height = $3\times 7$

                                         = 21 cm

Surface Area = $2\times \frac{22}{7}\times 10\times 21$

                      = $\frac{2\times 22\times 10\times 21}{7}$

                      = $\bold {1320\ cm^2}$

Case 2:If radius is doubled Radius = $2\times 10$

                                                          = 20 cm

Surface Area = $2\times \frac{22}{7}\times 20\times 7$

                      =$\frac{2\times 22\times 20\times 7}{7}$

                      =$\bold {880\ cm^2}$

Hence,in both cases Surface Area will be different.

Answer 2

Step-by-step explanation:

Check out the attached image

Hope it helpful to you..❤️✨️✌️