Question

if one angel of a parallelogram is 90°, show that each of its angles measure 90°​

Answer 1

Step-by-step explanation:

Consider ABCD be a parallelogram and measure of angle C is 90°. Thus, m∠A=m∠B=m∠C=m∠D=90°. Since, all the angles of the parallelogram are equal to 90, therefore ABCD is a rectangle, by the properties of rectangle. Hence proved.