Question

In Fig. 2, if l || m , then the value of x is: (A) 60 (B) 80 (C) 40 (D) 140​

Answer 1

Answer:

ACB + ACM = 180⁰

80⁰ + ACM = 180⁰

ACM = 100⁰

L || M

x + 60⁰ = 100⁰(alternate angle)

x = 100⁰-60⁰

x = 40⁰

Answer 2

Given :-

• l // m

Find :-

• Value of x

Solution :-

 ∠B = 60° { by Alternate Angle }

Now, In ∆ ABC

By using the angle sum property of the triangle :-

∠A +  ∠B +  ∠C = 180°

$\longrightarrow\angle{A = x}$

$\longrightarrow\angle{B = 60^{\circ}}$

$\longrightarrow\angle{C = 80^{\circ}}$

Substituting the respective values in it, we get :

↬ x + 60° + 80° → 180°

↬ x + 140° → 180°

↬ x = 180° - 140°

↬ x = 40°

Therefore, ( x → 40° )

Verification

↬ ∠A +  ∠B +  ∠C = 180°

↬ 40° + 60° + 80° → 180°

↬ 180° = 180°

LHS = RHS

Hence, Verified!!

Thus , Option (C) is correct.

• Angle sum property of Triangle

➹ According to the angle sum property of a triangle , the sum of all the sides of the triangle is equal to 180°.

• What is Parallel lines?

➹ Two different lines in a plane are said to be parallel, if there is no point common in them even through these lines are extended on both sides to any extent.