Question

One of the two equal angles of isosceles triangle are ${35}^o.$ Find the measure of the vertex angle.

• A. ${100}^o$
• B. ${110}^o$
• C. ${120}^o$
• D. ${130}^o$

Answer 1

Answer: (B)

${110}^o$

The equal angles in the isosceles triangle $={35}^o.$

Sum of the interior angles $={180}^o.$

${35}^o+{35}^o+x={180}^o$

${70}^o+x={180}^o$

$x={180}^o-{70}^o$

$x={110}^o.$

So, the vertex angle is ${110}^o.$