Answer:
90 degree
Step-by-step explanation:
∠ 1 , ∠2 and ∠3 are three interior angles of a triangle so the sum of these three angles are 180°
From the figure, ∠1 is a right angle means m∠1=90°
m∠1+m∠2+m∠3=180°
m∠2+m∠3=180°-m∠1
m∠2+m∠3=180°-90°
m∠2+m∠3=90°
