A triangle equals 180°. A right triangle has a 90° angle. So the other two angles added together will also need to equal 90°.
8x + 12x= 90°
20x= 90°
Divide both sides by 20.
x= 4.5°
Then plug in the answer for x into the other two angles.
8x=
8(4.5)= 36°
12x=
12(4.5)= 54°
Check your answer:
8x + 12x= 90°
36° + 54°= 90°
