Question

The figure below shows the steps Stacey took to construct an isosceles triangle.

A horizontal line segment XY and a perpendicular line segment AB that meets XY at point P is drawn. A semi-circle with its center at P and which meets the line segment at two points is drawn. Point Q lies on the arc to the right of AB. Point R lies on the arc below Q to the right of AB.

Which step in the construction was not required to construct the isosceles triangle?

constructing a perpendicular line AB

plotting the points Q and R

constructing the line segment XY

drawing an arc that cuts line