Question

Givery. ABCD is a parallelogram,Which would suffice to prove ABCD is a rectanglerDE BDDE AEDADOODCAB

Answer 1

It is given that ABCD is a parallelogram. So opposite sides of ABCD are equal and parallel to each other, which means,

`DA\cong CB\text{ and }DC\cong AB`

The diagonal of a parallelogram bisect each other. If diagonal of parallelogram are equal to each other then parallelogram is a rectangle. So sufficient condition for a parallelogram ABCD to be a rectangle is,

`DE\cong AE`

So parallelogram ABCD is rectangle if DE is equal to AE, as diagonal of rectangle are equal to each other.