In the diagram, MNR is a tangent to the circle centre O at N and ∠NOS = 108°. Find ∠OSN
A.
72°
B.
32°
C.
36°
D.
18°
Correct answer is C
The sum of angles in a triangle = 180º
(180 - 108)º = 72º
Isosceles triangle has both two equal sides and two equal angles.
∠OSN = ∠SON = \(\frac{72}{2}\)
= 36º