Question

In a circle radius 10cm, an arc PQ subtends an angle of ⁵/₁₂π radians at the centre of the circle. Calculate the radius of another circle whose circumference is equal to the length of arc PQ.   

Answer 1

Length of Arc PQ =    
                         =²⁵/₂π           
²⁵/₂π= 2πr  ∴ r = ²⁵/₂π × ¹/₂π      
                       =²⁵/₄ =6.25cm