ANSWER
Find out X and the measure of each side.
To proof
the diagram is given below
As given
angle D is congruent to angle E,
thus by using the property
if the two angle are equal to eachother than their opposite sides are also equal.
i.e
EF = DF
as given
DE= X + 4, EF= 4X - 8, DF = 7X-35
thus
4X -8 = 7X -35
solve
-3X = -27
[tex]X = \frac{27}{3}[/tex]
X = 9
therefore
DE= X + 4
= 9 + 4
= 13 unit
EF= 4X - 8
= 36 -8
= 28 unit
DF= 7X - 35
= 63 -35
= 28 unit
Hence proved
