Question

One of the angles of a triangle is ${130}^{\circ }$, and the other two angles are equal. What is the measure of each of these equal angles?

• A. ${25}^{\circ }$
• B. ${45}^{\circ }$
• C. ${35}^{\circ }$
• D. ${29}^{\circ }$

Answer 1

The correct option is A ${25}^{\circ }$

Given:
One of the angles of a triangle is ${130}^{\circ }$.
And the remaining two angles are equal.
Let us assume that the second and third angle be $x$.
We know that sum of all the angles of a triangle = ${180}^{\circ }$
${130}^{\circ }$ + $x$ + $x$ = ${180}^{\circ }$
${130}^{\circ }$+ $2x$ = ${180}^{\circ }$
$2x$ = ${180}^{\circ }$– ${130}^{\circ }$
$2x$ = ${50}^{\circ }$
$x=\frac{50}{2}$
$x$ = ${25}^{\circ }$
Therefore the two other angles are ${25}^{\circ }$ each.