Question

Find the angle which is equal to its supplement
A. ${80^0}$
B. ${90^0}$
C. ${110^0}$
D. ${154^0}$

Answer 1

Hint: To solve this question, we will use the definitions of supplementary angles which states that if two angles are supplementary, then their sum must be 180 degree and both angles should be equal.

Complete step-by-step answer:
Let two supplementary angles be \[{x_1}{\text{ and }}{x_2}\]
Where ${x_1} = {x_2} = x$ [supplementary angles are equal.]
We know that,
If two angles are supplementary then their sum is ${180^0}$
So, \[{x_1}{\text{ + }}{x_2} = 180\]
$
   \Rightarrow x + x = 180{\text{ [}}\because {\text{ }}{x_1} = {x_2} = x] \\
   \Rightarrow 2x = {180^0} \\
   \Rightarrow x = {90^0} \\
$
Hence, ${90^0}$ is equal to its supplement.

So, the correct answer is “Option B”.

Note: To solve this type of questions remember the definitions of these angles such as complementary angles. Two angles are said to be complementary when they add up to 90 degrees. Example: 50 degree +40 degree is equal to 90 degree. The definition of supplementary angles is mentioned in the question.