Answer:
c = 13
Step-by-step explanation:
In a rectangle the diagonals bisect each other, thus
FG = FI , substitute values
7c - 67 = c + 11 ( subtract c from both sides )
6c - 67 = 11 ( add 67 to both sides )
6c = 78 ( divide both sides by 6 )
We know FG and FI are equal to each other because F is the cross section of a rectangle.
FG = 7c - 67
FI = c + 11
FG = FI
7c - 67 = c + 11 Add 67 to each side so it will cancel on the left
7c = c + 11 + 67
7c = c + 78 Subtract c from each side so it cancels on the right
7c - c = 78
6c = 78 Divide each side by 6
6c/6 = 78/6
c = 78/6
