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Line Segments Ab and Cd Intersect at O Such that Ac || Db. If ∠Cab = 45° and ∠Cdb = 55°, Then ∠Bod =

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Question

Line segments AB and CD intersect at O such that AC || DB. If ∠CAB = 45° and ∠CDB = 55°, then ∠BOD =

Options

  •  100°

  •  80°

  •  90°

  •  135°

MCQ
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Solution

In the given problem, line segment AB and CD intersect at O, such that ,AC || DB , ∠CAB = 45° and  ∠CDB = 55° .

We need to find  ∠BOD

As  AC || DB

Applying the property, “alternate interior angles are equal”, we get,

 ∠OBD = ∠CAB

∠OBD= 55°  .......(1)

Now, using the angle sum property of the triangle

In ΔODB, we get,

∠OBD + ∠ODB + ∠BOD = 180°

 55° + 45° + ∠DOB = 180° (using 1)

∠BOD = 180 °- 100°

∠BOD = 80° 

Thus,∠BOD = 80°

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Chapter 11: Triangle and its Angles - Exercise 11.4 [Page 25]

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R.D. Sharma Mathematics [English] Class 9
Chapter 11 Triangle and its Angles
Exercise 11.4 | Q 12 | Page 25

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