Question:
The larger of two supplementary angles exceeds the smaller by 18 degrees. Find them.
Solution:
We know that the sum of supplementary angles will be $180^{\circ}$.
Let the longer supplementary angles will be' $y^{\prime}$.
Then, $x+y=180^{\circ} \cdots(i)$
If larger of supplementary angles exceeds the smaller by 18 degree, According to the given condition. We have,
$x=y+18 \cdots(i i)$
Substitute $x=y+18$ in equation $(i)$, we get,
$x+y=180^{\circ}$
$y+18+y=180^{\circ}$
$2 y+18=180^{\circ}$
$2 y=180^{\circ}-18^{\circ}$
$2 y=162^{\circ}$
$y=\frac{162^{\circ}}{2}$
$y=81^{\circ}$
Put $y=81^{\circ}$ equation $(i i)$, we get,
$x=y+18$
$x=81+18$
$x=99^{\circ}$
Hence, the larger supplementary angle is $99^{\circ}$
The smaller supplementary angle is $81^{\circ}$.