Find the measure of the missing angle

Answer: 55 degrees
Step-by-step explanation:
a+90+35=180 ==> a straight line measures 180 degrees and the angles a, a right angle, and 35 lie on that line. A 180 degree angle is called a straight angle. Also, if there is a tiny box in between an angle, that means that the angle is a right angle.
a+125=180
a+125-125=180-125
a=180-125
a=55 degrees