A pentagon has four of its angles equal. If the size of the fifth angle is 60o, Find the size of each of the four equal angles.
- 60o
- 108o
-
120o
- 150o
- None of the above
The correct answer is: C
Explanation
The sum of interior angle of pentagon(5 sides) = (2n - 4) x 90o
n = 5
(2 x 5 - 4) x 90o = 6 x 90o
= 540o
540o - 60o = 480o \(\div\) 4
= 120o