Question

Three angles form a straight angle and they are in the ratio 2 : 4 : 3.

Find the measure of the smallest angle among them.

• A. ${40}^{\circ }$
• B. ${30}^{\circ }$
• C. ${60}^{\circ }$
• D. ${80}^{\circ }$

Answer 1

The correct option is A

${40}^{\circ }$

The sum of all the three angles forming a straight angle $={180}^{\circ }$

Since the angles are in the ratio 2 : 4 : 3, let $x$ be a factor such that,

$2x+4x+3x={180}^{\circ }$

$9x={180}^{\circ }$

$x={20}^{\circ }$

Hence the three angles are:

$2x={40}^{\circ }$

$4x={80}^{\circ }$

$3x={60}^{\circ }$

So the smallest angle is ${40}^{\circ }$.