Answer:
1. CEF = 66 degress
2. JK = 8
GH = 16
Explanation:
Part 1
Since triangle DEF is formed by connecting midpoints of side of triangle ABC, according to midpoint theorem, the sides of triangles DEF parallel to sides os triangles ABC
so angle CEF is congruent to angle ABC = 66 degrees
Part 2
According to midpoint theorem: JK = 1/2GH
since 5x - 12 = 1/2(5x - 4)
2(5x - 12) = 5x - 4
10x - 24 = 5x - 4
10x - 5x = 24 - 4
5x = 20
x = 4
so JK = 5x - 12 = 5(4) - 12 = 8
GH = 5x - 4 = 5(4) - 4 = 16