Question

Find the value of in the triangle shown below.

0
=
80°
7
7
2
9

Answer 1

• We can see that the triangle has two equal sides. So, the triangle will have two equal opposite angles. It is an isosceles triangle.
• Given, an angle measures 80°.
• We take the measure of each of the two equal angles as x°.
• We know, the sum of all angles of a triangle is 180°.
• Therefore, by the problem

x + x + 80° = 180°

or, 2x = 180° - 80°

or, 2x = 100°

or, x = 100° ÷ 2

or, x = 50°

Answer:

The value of x in the triangle is 50°.

Answer 2

x = 50°

Explanation:

180° - 80° = 100°

100° ÷ 2 = 50°

50° + 50° + 80° = 180°