1. The problem asks which figures have perpendicular sides. 2. Perpendicular sides meet at a right angle (90 degrees). 3. Figures A and B have right angle corner marks, indicating their sides are perpendicular. 4. Figures C and D do not have right angle marks, so their sides are not perpendicular. 5. Therefore, the figures with perpendicular sides are A and B only. Final answer: A and B only