Make a line. Using the compass construct 2 circles from A to B and B to A. Construct a segment from A to B. Intersect the two circles to get point p. Construct line segments from p to A and from B to P. Next construct a segment from P to the line below. The intersection point is point X. The angle of X is 90 degrees.

Chapter 2 Activity 4b

First create line AB. Next construct a circle from the center P to A. Then add the intersection between the circle and the line to create point B. Next create two more circles using point A as the center for the first and point B as the center for the second circle. Construct a line segment from point P to the intersection of the two circles to create a point. The angle between these two points is 90 degrees.