Question

Q19. If one angle in a parallelogram is a right angle, how can we say that all the other angles are
right angles? Draw and label a parallelogram and explain it giving appropriate reasons.​

Answer 1

Answer:

Given - In a parallelogram ABCD, angle ADC = 90 degree

To prove - other angles of parallelogram is 90 degree

construction- draw diagonal AC and BD

proof - In triangle ACD AND BCD

AD= BC

AO=OC

DO=BO

therefore , triangle ACD congruent to triangle BCD

therefore , angle ADC = angle BCD ( BY CPCT )

but angle ADC + angle BCD = 180 degree

90 degree + angle BCD = 180 degree

angle BCD = 180 - 90

angt BCD = 90

similarly , angle CBA = 90

angle BAD = 90

proved

Step-by-step explanation:

hope you like this answer and Mark my answer as brilliant answer...........