Question

If the sum of two angles of a triangle is 123°, find the third angle.

• A. ${75}^o$
• B. ${57}^o$
• C. ${67}^o$
• D. ${76}^o$

Answer 1

The correct option is B ${57}^o$

According to the angle sum property of a triangle, the sum of the three interior angles is 180°.

The sum of two angles is given as ${123}^o$.

∴ Third angle = ${180}^o$ – ${123}^o$ = ${57}^o$