In the diagram, PTR is a tangent to the centre O. If angles TON = 108°, Calculate the size of angle PTN
-
A.
132o -
B.
126o -
C.
108o -
D.
102o
Correct Answer: Option B
Explanation
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°