First find the angle next to 123 123 + angle1 = 180
then fin the ngle next to 114 114 + angle2= 180
Now you can compute the third angle in the bottom tringle
Angle 3 = 180 - angle 2 - angle 1
this will also be the bottom angle in the right triangle
then the other angle in the right triangle will be 180 - 90 - angle 3
this will also be the angle in the bottom of the TOP triangle
the other two angles in the top triangle are = (and this includes 'x')
so subtract this bottom angle from 180 and divide by 2 to find 'x' Give it a try ! 