Question

Two adjacent angles on a straight line are in the ratio 5 : 4. Find the measure of each of these angles.

Answer 1

Let the two adjacent angles be 5x and 4x, respectively.
Then,
$$\begin{gathered} 5x+4x=180° \\ \Rightarrow 9x=180° \\ \Rightarrow x=20° \end{gathered}$$
Hence, the two angles are $5\times 20°=100°\text{and}4\times 20°=80°$.