A pentagon has four of its angles equal. If the size of the fifth angle is 60

^{o}, Find the size of each of the four equal angles.-
**A.**

60^{o} -
**B.**

108^{o} -
**C.**

120^{o} -
**D.**

150^{o} -
**E.**

None of the above

##### Correct Answer: Option C

##### Explanation

The sum of interior angle of pentagon

(5 sides) = (2n – 4) x 90^{o}

n = 5

(2 x 5 – 4) x 90^{o} = 6 x 90^{o}

= 540^{o}

540^{o} – 60^{o} = 480^{o} (div) 4

= 120^{o}