If the diagonals of a parallelogram are equal, then show that it is a rectangle

k...dats easy

GIVEN:ABCD is a parallelogram with diagonal AC=diagonal BD

PROOF:In triangles ABC and ABD,we have:

AB=AB[common side]

AC=BD[Given]

AD=BC[Opp.sides of  parallelogram are equal]

Therefore,Traingle ABC is =~ triangle ABD.[By SSS congruence rule]

Angle DAB is equal to Angle CBA [CPCT]....(1.)

But Angle DAB and Angle CBA is equal to 180 degrees.....(2.)

From (1.) and (2.),we get:

Angle DAB is equal to Angle CBA =1 right angle

the angles of quadrilateral are in ratio 3:5:9:13. Find all the angles of the quadrilateral.

abey the sum of all angle of a  quadilatial = 360 degrees , (3 + 5 + 9 + 13) divided by 360 = 12 so 3 x 12 , 5 x 12 , 9 x 12 , 13 x 12 = 36 degrees , 60 degrees , 108 degrees , 156 degrees !    

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Thanx alot

thanks a lot