Luas juring OPQ = 123,2 cm². Bersar sudut POQ =72°. berapakah panjang busur PQ pada juring tersebut? π=22 per 7

Luas juring OPQ = 72/360 x πr²
123,2 = 1/5 x 22/7 x r^2
123,2 = 22/35 x r^2
r^2 = 123,2 x 35/22
r^2= 196
r= akar 196
r = 14 cm

panjang busur PQ = 72/360 x 2πr
= 1/5 x 2 x 22/7 x 14
= 17,6 cm

L juring = 72°/360° x phi × r^2
L juring = 1/5 phi r^2
123,2 = 1/5 × 22/7 × r^2
22r^2 = 123,2 × 35
r^2 = 4312/22
= 196
r = akar 196
= 14 cm
panjang busur PQ = 72°/360°×(2×phi×r)
= 1/5×(2×22/7×14)
= 1/5×88
= 17,6 cm