Jawab:
panjang busur = ∠α/360 x 2 x π x r
= 60/360 x 2 x 22/7 x 21
= 1/6 x 2 x 22 x 3
= 22
c) Diketahui:
sudut α = 120
π = 22/7
panjang busur = 88
Ditanyakan: panjang jari-jari = ...?
Jawab:
panjang busur = ∠α/360 x 2 x π x r
88 = 120/360 x 2 x 22/7 x r
88 = 1/3 x 44/7 x r
88 = 44/21 x r
88 x 21/44 = r
r = 2 x 21
r = 42
d) Diketahui:
jari-jari = 100
π = 3,14
panjang busur = 31,4