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.
A
60o
B
108o
C
120o
D
150o
E
None of the above
Verified Correct Answer: C.
Step-by-Step Mathematical Solution
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
Source: Myschool Past Questions Archive (Record #32626)