A right angle is 90° or a quarter turn. It looks like the corner of a square or rectangle. You can spot right angles in doors, books or the edge of a ... angle but not a straight line.

ZACH: Let’s have a look at our design.Ah, one of the angle measurements is missing on this one.How do we work it out, Ada? ADA: You can see that the angles are on a straight line.We know that a ...