In the Given Figure, Abcd is a Cyclic Quadrilateral. If ∠Bcd = 100° and ∠Abd = 70°, Find ∠Adb. - Mathematics

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Short Note

In the given figure, ABCD is a cyclic quadrilateral. If ∠BCD = 100° and ∠ABD = 70°, find ∠ADB.

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Solution

It is given that ∠BCD = 100° and ABD = 70°

We have to find the ∠ADB

We have

A + C = 180°                     (Opposite pair of angle of cyclic quadrilateral)

So,

`angle A = 180° - 100°`

               = 80° 

Now in  Δ ADB   is  `angle A ` = 80°  and  `angle ABD` = 70°

Therefore,

`angle A + angle ADB + angle ABD = 180°`

       `80° + angleADB + 70° = 180°`

                              `angleADB = 180° - 150°`

                                           = 30°

Hence,  `angleADB` = 30°

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Chapter 15: Circles - Exercise 15.5 [Page 101]

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RD Sharma Mathematics for Class 9
Chapter 15 Circles
Exercise 15.5 | Q 4 | Page 101

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