In the figure, lines AB and CD intersect at O. If ∠AOC + ∠BOE = 70° and ∠BOD = 40°, find ∠BOE and reflex ∠COE. Anyone plz help with this que i am stuck with this que. for an hour .... plz help
Answers
SOLUTION :
∠AOC + ∠BOE = 70°
∠AOC + ∠COE + ∠BOE = 180°
[ linear pair ]
So,
if ∠AOC + ∠BOE = 70°
so,
→ 70° + ∠COE = 180°
→ ∠COE = 180 - 70
→ ∠COE = 110°
.
∠BOD = ∠AOC [ Vertically Opposite Angles ]
.
Now,
→ ∠AOC + ∠COE + ∠BOE = 180°
→ 40° + 110° + ∠BOE = 180°
→ 150° + ∠BOE = 180°
→ ∠BOE = 180° - 150°
→ ∠BOE = 30°
.
∠BOD + ∠DOA = 180° [Liner Pair]
→ 40° + ∠DOA = 180°
→ ∠DOA = 180° - 40°
→ ∠DOA = 140°
Hence,
reflex angle ( ∠COE ) = ∠AOC + ∠DOE + ∠BOD + ∠BOE
reflex angle ( ∠COE ) = 40° + 140° + 40° + 30°
reflex angle ( ∠COE ) = 250°
Given:∠BOD=40⁰
Since AB and CD intersects, ∠AOC=∠BOD(vertically opposite angles)
∠AOC=40⁰
Also,∠AOC+∠BOE=70⁰
⇒∠BOE=70 −∠AOC=70 − 40 = 30⁰
We need to find reflex∠COE
Reflex∠COE=360⁰ −∠COE
Now, ∠AOC+∠COE+∠BOE=180⁰
⇒∠COE+(∠AOC+∠BOE)=180⁰
⇒∠COE+(40⁰ + 30⁰ )=180⁰
⇒∠COE = 180⁰ −70⁰ = 110⁰
Reflex∠COE=360⁰ − 110⁰ = 250⁰