1. **Stating the problem:** Construct triangle ABC with sides AC = 9 cm, BC = 7 cm, and angle BAC = 90°. 2. **Understanding the problem:** We have a right triangle with angle BAC = 90°, so AC and AB are perpendicular. 3. **Constructing the triangle:** Draw segment AC = 9 cm. 4. Since angle BAC = 90°, draw segment AB perpendicular to AC at point A. 5. Mark point B on the perpendicular such that BC = 7 cm. 6. **Constructing the perpendicular bisector of line BC:** Find midpoint X of BC by calculating coordinates or measuring. 7. Draw the perpendicular bisector of BC passing through X. 8. **Finding point Y:** The intersection of line BC and its perpendicular bisector is point X itself (since bisector passes through midpoint). 9. **Constructing the circle:** Draw a circle with center Y (which is X) and radius XY (distance from X to Y is zero, so radius is zero, meaning the circle is a point at X). **Note:** The problem states "indicate the meeting point of line BC and bisector as Y" and "circle with Y and radius XY". Since Y lies on BC and bisector, Y is the midpoint X of BC, and radius XY = 0. **Final answer:** The circle centered at Y (midpoint of BC) with radius XY (zero) is a point circle at Y. **Summary:** Construct triangle ABC with AC=9 cm, angle BAC=90°, BC=7 cm, find midpoint Y of BC, draw perpendicular bisector of BC through Y, and draw circle centered at Y with radius XY=0.