These two angles (40° and 50°) are Complementary Angles, because they add up to 90°.Notice that together they make a Right Angle.
Lines are parallel if they are always the same distance apart (called "equidistant"), and will never meet.
Lines that are at right angles (90°) to each other.
Both Adjacent and Supplementary Angles:
Two angles whose measures add to 180 degrees. It is easy too to see this when the angles are adjacent like as shown below. Again, angles a and b adjacent because they share a ray (line in black) and a vertex (point in black called D), so they are adjacent angles.Now why are they supplementary?Notice also that the angle in blue measures 180 degrees because the angle is a striaght line and a straight line measures 180 degrees. Since the measure of angle a plus the measure of angle b = 180 degrees, a and b are supplementary