Question

in the given figure AC is a straight line find (1) ×(2) ∆ AOB​

Answer 1

Answer:

AOB and ∠COB are linear pairs

∴ ∠AOB + ∠COB = 180°

⇒ x + 25° + 3x + 15° = 180°

⇒ 4x + 40° = 180°

⇒ 4x = 180° – 40° = 140°

(i) ⇒ x = 140°/4 = 35°

Hence, x = 35°

(ii) ∠AOB = x + 25° = 35° + 25° = 60°

(iii) ∠BOC = 3x + 15° = 3 × 35° + 15°

= 105° + 15° = 120°

Answer 2

Answer:

Step-by-step explanation:

x+25+3x+15  =180              {straight angle}

4x+40=180

4x=180-40

4x=140

x=140/4

x=35

AOB = x+25= 35+25=60

1/2 of AOB = 1/2 of 60 = 30 degrees