Answer:
18) If ∠1 = 124° , then ∠4 = 56°.
19) if ∠2 = 48°, then ∠3 = 132°.
20) if ∠4 = 55°, then ∠2 = 55°.
21) if ∠6 = 120° , then ∠8= 120°.
22) if ∠7 = 50.5 , then ∠6= 50.5°.
23) if ∠3 = 118.7°, then ∠2= 61.3°
Step-by-step explanation:
Given two parallel lines a and b.
And other line, which is called transversal line cuts these two parallel lines to make 8 angles.
Now,
18) Given, ∠1 = 124°
Now, sum of consecutive interior angles made by transversal line with parallel lines = 180° .
⇒∠1 + ∠4 = 180°
⇒∠a = 180° - 124° = 56°.
19) ∠2 = 48°.
as sum of consecutive interior angles made by transversal line with parallel lines = 180° .
∠2 + ∠3 = 180°.
⇒ ∠3 = 180° - 48° = 132°.
20) ∠4 = 55°
Alternate angles made by transversal line with parallel lines are equal .
⇒∠2 = ∠4 = 55°.
21) ∠6 = 120°
As corresponding angles made by transversal line with parallel lines are equal. ∠6 = ∠3 = 120°.
now, also opposite angles are equal
⇒ ∠3 = ∠8 = 120°.
22) ∠7 = 50.5
As corresponding angles made by transversal line with parallel lines are equal. ∠7 = ∠2 = 50.5°.
now, also opposite angles are equal
⇒ ∠2 = ∠6 = 50.5°.
23) ∠3 = 118.7°
as sum of consecutive interior angles made by transversal line with parallel lines = 180° .
∠3 + ∠2 = 180°.
⇒ ∠2 = 180° - 118.7° = 61.3°
