Question

I dont understand this??

Answer 1

ZY = 23

Explanation:

Given in the picture:

ZY = 7a + 2

ZD = DX, diagonals of parallelograms bisect each-other so

3(2a+1) = 9a -6 , given in the picture

6a +3 = 9a - 6, subtract 9a and 3 from both sides

6a -9a = -6 -3, combine like terms

-3a = -9, divide both sides by -3

a = 3

ZY = 7a + 2

ZY = 7·3 + 2

ZY = 23