Question

Find the value of x in each diagram.

Answer 1

4. 25 5. 80 6. 30

Explanation:

All triangles add up to 180.

The triangle in #4 is right, so 90° + 65° = 155°

180° - 155° = 25°

x=25

#5.

50° + 50° = 100°

180° - 100° = 80°

x=80

In #4 the triangle is an equilateral, so all the angles will be equal. 2x + 2x + 2x = 180

6x = 180

x = 30

Answer 2

Explanation:

The sum of interior angles in a triangle is equal to 180°

Two of the angle measures are given in each triangle so to find the third angle measurement we need to subtract the sum of two of the interior angles

4.

180 - (65 + 90) = x

180 - 155 = x

25 = x

5.

180 - (50+5) = x

180 - 100 = x

80 = x

For the 6th question all side lengths are equal so the angle measures also equal and 60 each

2x = 60

x = 30