Answer:

Explanation:
Given the rhombus CDEF, sides FC and CD are adjacent sides.
Using coordinate geometry, to proof that a quadrilateral is a square, with regards to the slope, the slope of adjacent segments must be negative reciprocals.
In fact, by definition: Two lines with slopes
are perpendicular if:

Therefore if :
- FC and CD are adjacent segments
- Slope of FC=25
For the rhombus to be a square:
Slope of CD
