Tolong bantu ya...... No 1

Kll = 2.phi.r
     = 2. 22/7 . 21cm
     = 132 cm
L   = phi.r^2
     = 22/7.21cm.21cm
     = 1286 cm^2

K=πd
=22/7•42
=132cm

Luas=πr²
=22/7•21•21
=22•3•21
=66•21
=1386cm²