The answer is 21, 21 is the value of x
The length of the curved surface is the circumfrence of a circle with radius r = 10/2 = 5 decimeters.
Length of curved surface = 2π x 5 = 10π ≈ 31.4 decimeters.
You do not. If you reduce 64:60, you will get 16:15 which is not the same as 16:4
