Question

Choose the correct word and fill in the blanks :

Supplement of an obtuse angle is an ………….. angle. (acute / obtuse)

Answer 1

Acute angle :

Angle measures greater than $0°$ and less than $90°$ is called an acute angle.

Obtuse angle :

Angle measures greater than $90°$ and less than $180°$ is called an obtuse angle.

As we know that the sum of supplementary angles is $180°$.

Supplement angle : One angle from a pair of supplementary angles.

So, in a pair of supplementary angles if one angle is an obtuse angle then another angle will be an acute angle. As shown in the figure below :

Here $60°$ is an acute angle and $120°$is an obtuse angle.

Sum of $60°$and $120°$ is $180°$ i.e. $60°+120°=180°$

Hence, supplement of an obtuse angle is an acute angle.