Question

Ln triangle PQR, angle P-Q=20 and angle Q-R=50, find the value of angle R​

Answer 1

R = 20

Explanation:

The sum of measures of angles in triangle is always 180°:

P + Q + R = 180

Q - R = 50 ⇒ Q = 50 + R

P - Q = 20 ⇒ P = 20 + Q = 20 + 50 + R = 70 + R

so:

P + Q + R = 180

70 + R + 50 + R + R = 180

120 + 3R = 180

3R = 180 - 120

3R = 60

R = 60:3

R = 20