Diameter lingkran 42 cm. Berapakah luas keliling lingkaran ?

d = 42 cm
r = 21 cm

Luas lingkaran
= π x r²
= 22/7 x 21 cm x 21 cm
= 1.386 cm²

Keliling lingkaran
= π x d
= 22/7 x 42 cm
= 132 cm