Final answer:
The construction of tangent lines from point A to a circle with center O involves drawing a circle with midpoint M of segment OA and connecting the two intersection points B and C with point A to form the tangents AB and AC.
Step-by-step explanation:
The student's question is related to the construction of tangent lines to a circle using a compass and straightedge. To complete the construction process after finding the midpoint M of segment OA, where O is the center of the circle and A is the external point:
- Draw a circle centered at M that passes through O and intersects the original circle at two points; let's call these points B and C.
- Draw segments AB and AC. These segments are the required tangent lines to the original circle from point A since they touch the circle exactly at points B and C, respectively.
By the tangent radius theorem, we know that a tangent to a circle is perpendicular to the radius at the point of tangency. Hence, lines AB and AC, both tangent to the circle at B and C, will be perpendicular to the radii OB and OC, respectively.