Question

A side of the triangle below has been extended to form an exterior angle of 159º. Find the value of x.

Answer 1

Answer:

x = 69

Step-by-step explanation:

The exterior angle is equal to the sum of the opposite interior angles in a triangle

x+90 = 159

Subtract 90 from each side

x +90-90 = 159-90

x =69

Answer 2

Answer:

One of the interior angles is given as 90°

Move on to the exterior angle with 159°. Since one part of the altitude is given to be 159°, we can find the other part (let's name it y) because both add up to 180°(linear pair).

159+y = 180

y = 180-159

y = 21°

Now finally find x.

All the interior angles of the triangle result up to 180°

90+21+x = 180

111+x = 180

x = 180-111

x = 69°