Ab=25
dc=5x
ad=y+5
bc=2y

quadrilateral abcd is a parallelogram if both pairs of opposite sides are congruent. show that quadrilateral abcd is a parallelogram by finding the lengths of the opposite side pairs.

a)10,5
b)25,10
c)25,15
d)50,20

First, we have to find the values of the variables.
AB = DC, so 25 = 5x.
25/5 = 5, so x = 5
AD = BC, so 2y = y + 5.
Subtract y from both sides:
y = 5
Now we know both x and y equal 5.
AB and BC are adjacent, so we can use those two.
AB = 25
BC = 2(5) = 10
Option B is the correct answer