Question

PQ and PR touch the circle with centre o at A and B respectively. If angle OPB=30° and OP=10cm , then radius of the circle is

Answer 1

Your ans is 5cm
In triangle POV sin30=OB/OP
1/2=OB/10
OB=5cm

Answer 2

Explanation:

from figure , in triangle OPB

cos30° = PB/10 ⇒√3/2 = PB/10  ⇒PB = 5√3 now  in right angle triangle OPB

(5√3)² +(OB)² = 100

  OB  = 5