Volume of a cylinder =πr2h Volume =20mcm3 Height =5cm Substitute volume and height into the equation and solve for the value of r, radiu 20π=π×r2×5 Divide both sides of the equation by π×5 to make r the subject.
20π
π×5
=
π×r2×5
π×5
4=r2 Take square root of both sides or r is a value when multiplied by itself will give 4 , which is 2 because 2×2=4 2=r Thus 2×2=r2 Every number is raised to the power 1 21×21=r2 From the law of indices, am×an=am+n
21+1=r2 22=r2 Since the powers are the same, the bases are also the same 2=r