WAEC - Mathematics (2015 - No. 16)

In the diagram, PTR is a tangent to the centre O. If angles TON = 108°, Calculate the size of angle PTN

132^o

126^o

108^o

102^o

In the diagram; 108° + x + x = 180° (sum of angle in a triangle)

108° + 2x = 180°

x = 180° - 108°

= 72°

x = \(\frac{72^o}{2}\)

= 36°

(Angle between tangent and a chord through the point of contact)

Hence, angle PTN = 90 + 36

= 126°