Answer:
[tex] x = 67.5 \degree[/tex]
Step-by-step explanation:
[tex]x + 3x + 90 \degree = 360 \degree \\ \\ \implies \: 4x = 360 \degree - 90 \degree \\ \\ \implies \: 4x = 270 \degree\\ \\ \implies \: x = \frac{270 \degree}{4} \\ \\ \implies \: x = 67.5 \degree[/tex]
