in the given figure, prove that angle ADC= angle A+B+C
Answers
∠ADC = ∠A + ∠B + ∠C
Step-by-step explanation:
The image of the question is attached below.
Given figure ABCD.
To prove that ∠ADC = ∠A + ∠B + ∠C
Construction: Join BD
By exterior angle property of triangle,
An exterior angle of triangle is equal to the sum of the two opposite interior angles.
In triangle ABD,
∠1 + ∠2 = ∠5 ----------- (1)
Similarly in triangle CBD,
∠4 + ∠3 = ∠6 ----------- (2)
Adding equation (1) and (2), we get
∠1 + ∠2 + ∠4 + ∠3 = ∠5 + ∠6
⇒ ∠1 + (∠2 + ∠3) + ∠4 = ∠ADC (using figure)
⇒ ∠A + ∠B + ∠C = ∠ADC
Switch the sides.
∠ADC = ∠A + ∠B + ∠C
Hence proved.
To learn more...
1. In the given figure AD=BC and angle ADC = angle BCD.
Prove that AC =BD
https://brainly.in/question/7654554
2. In the given figure, ABCD is a quadrilateral in which AB || CD and AD || BC.Prove that angle ADC = angle ABC
https://brainly.in/question/11637647