Question

In a quadrilateral ABCD angle A is equal to angle D is equal to 90 degree. Prove that AC square + BD square is equal to AD square + BC square + 2 CD multiply AB.


Please tell the right answer.... ​

Answer 1

Step-by-step explanation:

Extend AB and DC to intersect at C

In ∆AOD angle AOD = 90°

because Angle A +Angle D = 90°

now, AC² = AO² + OC² 1

BD² = OB² + OD² 2

Add equation 1 and 2

AC² + BD² = OA² + OD² + OC² + OB²

AC² + BD² = AD² + BC²

Hence proved

Hope it helps you