J and M are base angles of an isosceles trapezoid JKLM. If the measure of angle J = 23x+4 and measure of angle M =12x+15, find the measure of angle K
The sum of angles J and M will be 180°.
J + M = (23x + 4) + (12x + 15) = 180
35x + 19 = 180
35x = 161
x = 4.6
Angle K will have the same size as angle M: 12(4.6) + 15 = 70.2°