Question

A triangle has the angles $35°\mathrm{and}35°$and find the third angle and classify the triangle.

• A. $110°,\mathrm{Isosceles}\mathrm{triangle}$
• B. $110°,\mathrm{Scalene}\mathrm{triangle}$
• C. $100°,\mathrm{Scalene}\mathrm{triangle}$
• D. $100°,\mathrm{Isosceles}\mathrm{triangle}$

Answer 1

The correct option is A $110°,\mathrm{Isosceles}\mathrm{triangle}$

Let the third angle be $x°$.
Using angle sum property we get:
$x°+35°+35°=180°x°=180°-70°x°=110°$
As two angles are equal, so the sides are also equal. Hence, it is an isosceles triangle.