Mathematics for IGCSE & O level - Geometrical Terms (Section 5 - No. 10)
If two lines intersect forming four angles, and one angle is 90 degrees, what are the measures of the other three angles?
90, 90, 90
45, 45, 90
60, 60, 60
120, 60, 90
Uitleg
If one angle is 90, the others will also be 90.