Question

Two angles of a triangle are ${50}^{\circ }$ and ${70}^{\circ }$. What is the measure of the third angle?

• A. ${60}^{\circ }$
• B. ${70}^{\circ }$
• C. ${50}^{\circ }$
• D. Can't be determined.

Answer 1

The correct option is A ${60}^{\circ }$

Angle sum property suggests that the sum of 3 angles of a triangle should be equal to ${180}^{\circ }$.
Let the third angle be x.
x + 50 + 70 = 180
x = 180 - 120 = ${60}^{\circ }$