In an isosceles triangle, if the unequal angle is five times the sum of the equal angles, then each equal angle is:
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 15°.
Let the measure of each equal angle be x and the measure of unequal angle be y.
According to the given question,
y = 5(x + x)
⇒ y = 10x
Now, sum of all the angles of triangle is 180°.
⇒ x + x + y = 180°
⇒ 2x + 10x = 180°
⇒ 12x = 180°
⇒ x = 15°