Anonymous

A semi-circle has a perimeter of 16 cm. pi r + 2 r = 16 r(pi + 2) = 16 pi r = 16 - 2r r = 16/(2 + π) The area of the semi-circle: (π r^2)/2 ≈ 15.2112 15.2112 cm^2

Anonymous

Perimeter of a semicircle is the arc, pi*r (because it's half the circumference 2pi*r of the circle), plus the diameter, the straight line across, 2*r. So perimeter = pi*r + 2*r = (pi + 2)r. Solve for r. Area is (1/2) pi*r^2. Plug in r.

Anonymous

(2+π)r = 16 A = area = πr^2/2 = (π/2)[16/(2+π)]^2 = 15.21 cm^2

Anonymous

Show your work and I'll help you.