to find x of a 90 degree angle and a 180 degree angle you take what you have and count up until you reach your number of 90 or 180 to get the answer of that angle
to tell what a 90 degree angle look for a right triangle or any angle below like an acute angle
to find a 180 degree angle look for an obtuse angle or the angle that creates a straight line
You know that the interior angles of a triangle equal 180 degrees, and you know that two of the angles are 90 and 42. Do 180-90-42, and the last angle is 48.
