tentukan luas selimut bola jika di tentukan jari jarinya (π=22/7) a.10,5cm b.49cm

1. A. L = 4 × phi × r^2

= 4 × 22/7 × 10,5^2

= 4 × 22/7 × 110,25

= 4 × 22 × 15,75

= 1.386 cm^2

B. L = 4 × phi × r^2

= 4 × 22/7 × 49^2

= 4 × 22/7 × 2.401

= 4 × 22 × 343

= 30.184 cm^2



2. A. L = 4 × phi × r^2

= 4 × 3,14 × 5^2

= 4 × 3,14 × 25

= 314 cm^2


B. L = 4 × phi × r^2

= 4 × 3,14 × 6^2

= 4 × 3,14 × 36

= 452,16 cm^2