tentukan jari jari lingkaran jika diketahui luasnya: a.1256 cm2 b.616 cm2

A.
L = 22/7 xrxr
1256 = 7/22 x 1256
R = √400
R = 20 cm
B.
L = 22/7 xrxr
616 = 7/22 x 616
R =√ 196
R = 14 cm

A. L = Phi × r^2

1.256 = 3,14 × r^2

r^2 = 1.256 ÷ 3,14

r^2 = 400 (diakarkan pangkat 2)

r^2 = 20^2

jdi jari2 nya 20^2


B. L = phi × r^2

616 = 22/7 × r^2

r^2 = 616 ÷ 22/7

r^2 = 616 × 7/22

r^2 = 4.312/22

r^2 = 196 (diakarkan pangkat 2)

r^2 = 14^2

jdi jari2 nya 14