Answer:
∠B = 60°
Step-by-step explanation:
They are supplementary angles, which means they add up to 180°.
∠B + ∠A = 180
? + 120 = 180
? = 180 - 120
? = 60°
x²+x²=9²
2x²=81
x²=81/2=(81×2)/4
x=9√2/2≈4.5√2≈6.36
9.
x²+x²=11²
2x²=11²
x²=11²/2
x=11/√2=11√2/2≈7.78
B