Length of the side CD is 12.8 feet.
Explanation.
Given:
The length of the side DE = 12 feet.
Angle C = 70 degree.
Angle E = 90 degree.
The objective is to find the length CD.
Consder the side CD as hypotenuse.
For the relationship between oposite side and hypotenuse side use trigonometric ratio of sin theta.
Hence, the length of CD is 12.8 feet.