Question

find unknown marked angle
ans 76 I want solution​

Answer 1

Answer:

Solution:

i) In the figure (i),

∠A + ∠B + ∠C = 180°

(Sum of angles of a triangle)

b° + 50° + b° = 180°

⇒ 2b° + 50° = 180°

⇒ 2b° = 180°- 50° = 130°

⇒ b° = 130°/2 = 65°

Hence ∠A = b° = 65°

And ∠c = b° = 65°

(ii) In the figure (ii)

∠A + ∠B + ∠C = 180°

(Sum of angles of a triangle)

x + 90° + x° = 180°

2x° + 90° = 180°

2x° = 180°- 90°

2x° = 90°

x° = 90°/ 2 = 45°

Hence ∠A = x° = 45°

And ∠C = x° = 45°

(iii) In the figure (iii)

∠A + ∠B + ∠C = 180°

(Sum of angles of a triangle)

K° + k° + k° = 180°

3k° = 180°

K° = 180°/3 = 60°

Hence ∠A = K° = 60°, ∠B = k = 60°

and ∠C = K° = 60°

(iv) In the figure (iv)

∠A + ∠B + ∠C = 180°

(Sum of Angles of a triangle)

(m° - 5") + 60° + (m° + 5°) = 180°

m° - 5° + 60° + m° + 5° = 180°

2m° = 180° - 65 + 5

2m° = 120°

∴ m° = 120°/60°

Hence ∠A = m° – 5° = 60°– 5° = 55°

and ∠C = m° + 5° = 60° + 5° = 65°