Answer:
a) 180 degree
b) 180 degree
c) 180 degree
d) m∠3
e) m∠3
Explanation:
a) We know that if two angles are supplementary then their sum = 180 degree.
In the given problem m∠1 and m∠2 are supplementary .Therefore m∠1+m∠2 =180°
b) We are given that m∠2 and m∠3 are supplementary. Therefore m∠2+m∠3 = 180°
c) m∠1+m∠2 = 180°
 m∠2+m∠3 = 180°
 equate equation 1 and equation 2:
 m∠1+m∠2=m∠2+m∠3
d) m∠1+m∠2=m∠2+m∠3
 Subtract m∠2 from both sides 
  m∠1+m∠2-m∠2=m∠2-m∠2+m∠3
 m∠1=m∠3
e)  m∠1≅m∠3 ....