Answer:
Step-by-step explanation:
7) PQ // RS, RQ is transversal
x = 38 {Alternate interior angles are congruent}
In ΔPQR ,
x + y + ∠P = 180 {Angle sum property of triangle}
38 + 90 + y = 180
128 + y = 180
y = 180 - 128
y = 52
9) Construct XY // AB
XY // AB & AC is transversal
∠1 = ∠4 ---------(I) {alternate interior angles are equal}
XY // AB & BC is transversal
∠3 = ∠5 ---------(II) {alternate interior angles are equal}
∠1 + ∠2 + ∠3 = 180 {straight line angles}
∠4 + ∠2 + ∠5 = 180 {From (I) & (II) }
Sum of three angles of triangle is 180.Hence proved.
