Question

In rhombus ABCD if angle A is 79 degrees then the value of angle CDB

Answer 1

Solution:-Given that ABCD is a rhombus and DAB = 79°
Since, ABCD is a rhombus
so∠ ABC = ∠ CDA and ∠ DCB = ∠ DAB = 79° .............(1)
And we know that,∠ DAB + ∠ ABC + ∠ DCB +∠ CDA = 360°
⇒ 79° + ∠ ABC + 79° + ∠ CDA = 360°
∠ ABC + ∠ CDA + 158° = 360°
∠ ABC + ∠ CDA = 360° - 158°
∠ ABC + ∠ CDA = 202°Since,
∠ ABC = ∠ CDA So,
∠ ABC + ∠ ABC = 202°
2∠ ABC = 202°
∠ ABC = 101°Thus,
∠ CDB = 1/2(∠ ABC)
= 1/2(101°)
∠ CDB = 50.5°Answer.