Question

Berapa luas lingkaran yang berdiameter 28cm?

Answer 1

R = d : 2
  = 28 cm : 2
  = 14 cm

L = π × r²
   = 22/7 × 14²
   = 22/7 × 196
   = 22 × 28
   = 616 cm²

Answer 2

R = 1/2d
r = 1/2 28
r = 14cm

L = phi r^2
= 22/7 14x14
= 616 cm^2

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