Question

ABCD is a parallelogram. Find the values of x and y. Solve for the value of z, if z=x−y.

A. -10
B. -20
C. 20
D. 30

Answer 1

I can confirm that the answer is right.

Parallelograms have equal opposite sides. Do the math:

x - y = z

40 - 20 = 20

z = 20

Answer 2

C

Explanation:

Parallel and opposite sides of a parallelogram are equal. Hence, we can say:

x + 30 = 2x - 10

and

2y-10 = y +10

Solving first one, we get:

x + 30 = 2x - 10

30+10 = x

x = 40

Also

2y - 10 = y + 10

y = 10 + 10

y = 20

Now, z = x - y, so

z = 40 - 20 = 20

Answer C is right.