we know that
If two figures are congruent, then its corresponding sides and its corresponding angles are congruent
in this problem
we have that
The triangle ABC is an isosceles right triangle
that means, that the triangle ABC has two equal sides and two equal interior angles
therefore
In the right triangle FGH we have that
FG=GH
substitute the given values
2x+7=7y=49
so
2x+7=49 --------> 2x=49-7 -------> 2x=42 -------> x=21 mm
7y=49 ------> y=7 mm
Find the value of z
3z+51=69 ------> 3z=69-51 ------> 3z=18 -------> z=6 mm
