Answer:
30°
Step-by-step explanation:
A triangle always adds up to 180° so since one side of the triangle is already 90°, that means the other two sides add up to be 90° as well.
[tex]x + 2x = 90 \\ 3x = 90 \\ \frac{3x}{3} = \frac{90}{3} \\ x = 30[/tex]
