Klmn is a rectangle. angle n measures (12a+24) find the value a

If the polygon or figure is a rectangle, it is given that the measure of all the angles is 90°. In this item, since we are given that the polygon is triangle, the equation that would allow us to solve for the unknown variable is,
                                      90 = 12a + 24
The value of a from the equation is 5.5.

You didn’t put the necessary image to solve the question : p