Question

(a) Find the value of angle which is supplementary to itself. [2 MARKS]
(b) Find the angle which is double of its supplement.

Answer 1

Solution: 1 Mark each

(a) Let the value of angle is x.

As we know that sum of supplementary angles is ${180}^{\circ }$.

Therefore value of its supplementary angle $={180}^{\circ }-x$

According to question, $x={180}^{\circ }-x$

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

$\Rightarrow x={90}^{\circ }$

(b) Let the value of the angle be x.

Double of the angle = 2x.

$\therefore x+2x={180}^{\circ }$

$\Rightarrow 3x={180}^{\circ }$

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

$\therefore$ The angle which is double its complement = 2x = ${120}^{\circ }$