Diketahui keliling lingkaran 132cm,maka luas lingkaran adalah

keliling = 2 x (phi) x r
132 = 2 x 22/7 x r
r = 132/2 x 7/22 = 21

luas = (phi) x r^2 = 22/7 x 21 x 21= 1386

2πr = keliling
2πr = 132
πr = 66
r = 66÷π
r = 21 cm

Luas lingkaran
= πr²
= 22/7 × 21 × 21
= 22 × 3 × 21
= 66 × 21
= 1.386 cm²

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#Semoga bermanfaat ^_^