Answer:

Step-by-step explanation:
In isosceles trapezoid JKLM,
Given:
and 
Since, JKLM is an isosceles trapezoid so each pair of base angles is congruent.


As, we know that the sum of the angle of a trapezoid is 
The angles are:


Therefore,

Combine like terms;

Subtract 40 from both sides we get;

Simplify:

Divide both sides by 56 we get;

To find the angle of
:

Simplify:

Therefore, the value of angle of 