Question

please give answer quickly .very urgent​

Answer 1

Answer:

∠7 = 100°

∠8 = 80°

Step-by-step explanation:

We know that ∠1 + ∠4 = 180° (Linear pair)

Given,

∠1 = 2x+y

∠4 = x + 2y

Substituting in the first eqn.,

∠1 + ∠4 = 180°

2x+y + x + 2y = 180

3x + 3y = 180

⇒ x + y = 60                    → 1

l ║ m

So, ∠2 = ∠6 (Corresponding angles)

We also know that ∠2 = ∠4 (Vertically opp. angles)

Equating both, we get

∠4 = ∠6

Given, ∠6 = 3y + 20

∴ ∠4 = ∠6

      x + 2y = 3y + 20

x + 2y - 3y = 20

       x  - y = 20       →2

Adding eqn. 1 and 2,

x + y = 60

x - y = 20

---------------

 2x = 80

∴ x = 40°

  x - y = 20

40 - y = 20

      -y = 20 - 40

⇒ y = 20°

Now, we have to find ∠7 and ∠8

∠6 = ∠8 (Vertically opp. angles)

∠6 = 3y + 20

     = 3 × 20 + 20 = 60 + 20

∴ ∠6 = 80°

⇒ ∠8 = 80°

∠7 + ∠8 = 180   (Linear pair)

∠7 + 80 = 180

∴ ∠7 = 100°

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