Question

The interior angles of regular polygon measure 150⁰ each. The number of diagonals of the polygon is

• A. 36
• B. 45
• C. 54
• D. 60

Answer 1

Answer: (C)

54

Answer 2

Each exterior angle = 30⁰.

∴ Number of sides = $\frac{360^{o}}{30} = 12$

Number of diagonals = $12C_{2} - 12 = 54$