ABCD is a quadrilateral in which angle BAD =105, angel BCD =150 and BC= 13cm . find AC? please solve this question About the author Claire
Answer: (i) Join BD Now, ABCD is a cyclic quadrilateral ∴ ∠BAD + ∠BCD = 180° (Opposite angles of a cyclic quadrilateral) => ∠BAD + 150° = 180° => ∠BAD = 180° – 150° = 30° (ii) ∠ABD = 90° (Angle in a semi-circle) Now, In △ABD, we have ∠ABD + ∠BAD + ∠ADB = 180° 90° + 30° + ∠ADB = 180° => ∠ADB = 180° – 120° = 60° Reply
Answer:
(i) Join BD
Now, ABCD is a cyclic quadrilateral
∴ ∠BAD + ∠BCD = 180° (Opposite angles of a cyclic quadrilateral)
=> ∠BAD + 150° = 180°
=> ∠BAD = 180° – 150° = 30°
(ii) ∠ABD = 90° (Angle in a semi-circle)
Now, In △ABD, we have
∠ABD + ∠BAD + ∠ADB = 180°
90° + 30° + ∠ADB = 180°
=> ∠ADB = 180° – 120° = 60°