Answer:
Part 1)
and

Part 2)
Part 3) m∠KLJ=

Explanation:
Part 1)
we have

Find the coordinates of the midpoint JK
the x-coordinate of the midpoint JK is equal to

the y-coordinate of the midpoint JK is equal to

The midpoint JK is the point

Find the coordinates of the midpoint LK
the x-coordinate of the midpoint LK is equal to

the y-coordinate of the midpoint LK is equal to

The midpoint LK is the point

The answer part 1) is
the endpoint coordinates for the midsegment of △JKL that is parallel to JL are the points
and

Part 2)
we know that
The diagonals bisect the parallelogram into two congruent triangles
In the parallelogram ABCD

substitute the values

Solve the quadratic equation
The formula to solve a quadratic equation of the form
is equal to
in this problem we have
so
substitute in the formula
Find the value of BD
Substitute the value of

Part 3)
we know that
The diagonals bisect the parallelogram into two congruent triangles
In the parallelogram JKLM
m∠KLJ=m∠MLJ
we have that
m∠MLJ=

therefore
m∠KLJ=
