What is the area and radius of a circle if it 14cm?

Answer 1

If what is 14cm? The diameter? The circumference?

d = diameter, r = radius, C = circumference, A = area, pi = approx. 3.14

If d = 14cm, then r = 7cm.

A = (pi)r2 = (pi)(7)2 = (3.14)(49) = 153.86 = about 154cm2.

If C = 14cm, use the formula C = 2(pi)r:

14 = 2(pi)r

r = 14/(2pi) = 14/6.28 = about 2.229 = about 2.23cm.

Then A = (pi)r2 = (3.14)(2.229)2 = 3.14(4.970) = about 15.6 cm2.