We need to solve first the value of x from the given figure.
Angle 3 and the angle = 10x have the same measurements because they are pair VERTICAL ANGLES.
The angle = 10x and the angle = 4x + 42 have equal angle measures as well because they are pair CORRESPONDING ANGLES.
Therefore in solving angle 3, we start by solving angle = 10x and angle = 4x + 42. That is by equating the two given angles. We have 10x = 4x +42. Solving for x, we get x = 7.
To solve for ANGLE 3. we simply substitute x = 7 to angle = 10x which also equal to angle 3. Therefore, ANGLE 3 measures, 70 degrees. (10*7)
