tentukan keliling dan luas juring 80% jari jari 9cm

K = 80% × 2 × π × r
= 80/100 × 2 × 3,14 × 9 cm
= 45,216 cm

L = 80% × π × r × r
= 80/100 × 3,14 × 9 cm × 9 cm
= 203,472 cm²