Question

If one angle of a triangle is ${40}^{\circ }$ and the other two angles are in the ratio 3:4. Then the largest angle in the triangle is

• A. ${90}^{\circ }$
• B. ${80}^{\circ }$
• C. ${100}^{\circ }$
• D. ${70}^{\circ }$

Answer 1

The correct option is B ${80}^{\circ }$

Given, one angle of a triangle = ${40}^0$

Let the other angles be 3x and 4x

Then, according to the angle sum property, ${40}^{\circ }+3x+4x={180}^{\circ }$

$7x={140}^{\circ }$

$x={20}^o$

Hence, the largest angle is $4\times 20={80}^{\circ }$.