Answer
The equations that will help solve this include
c + 5 = 11
d + 4 = 14
On solving this, we have
c = 6
d = 10
Step-by-step explanation
The key to answering this question, is to note that for a parallelogram, the diagonals of the parallelogram bisect each other.
This allows us to note that each of the diagonals have been broken down into two equal parts. So, we can write that
c + 5 = 11
And
d + 4 = 14
We can then solve these
c + 5 = 11
Subtract 5 from both sides
c + 5 - 5 = 11 - 5
c = 6
d + 4 = 14
Subtract 4 from both sides
d + 4 - 4 = 14 - 4
d = 10
Hope this Helps!!!