Geometry Practice : Angles in triangle

This quant practice question tests your understanding of basic properties of sum of angles in a triangle and elementary number properties.

Question

If the largest angle in a triangle is 70^o, what is least possible value of the smallest angle of the triangle?

1. 69^o
2. 1^o
3. 40^o
4. 39^o
5. 41^o

  Correct Answer      Choice (C). 40^o

Explanatory Answer

The sum of the interior angles of a triangle is 180^o.

The question states that the largest of the angles is 70^o.

Objective: Find the least possible value of the smallest of the three angles.

The least value for the smallest angle will be when the other two angles are as large as possible.

The largest value that the other two angles can take is 70^o each.

Therefore, the least value of the smallest of the angles = 180 - 70 - 70 = 40^o

  The correct answer is Choice (C).