Construct a Tangent From a Point Outside a Circle
- Author:
- Michelle Jones Teacher
1) Draw a line connecting the point C to the center of the circle A.
2) Construct the perpendicular bisector of that line
a)Place a point on the line
b) Using the compass tool create a circle with a radius from that new point to A, centered at A.
c) Without creating a new compass, click the new point, then A but this time move the compass circle to be centered at C (We wanted the same radius compass just centered at C this time not A)
d) Click Intersect then select the two circles you just drew. Their intersection points will appear
e) Create a line segment between these two points, this is the perpendicular bisector
3) Create a compass circle with a center of this new midpoint and a radius to either A or C. So the circle should go through A and C with a center of the new midpoint
4) Where that circle intersects the original circle are the points of tangency. Click intersect then select the new circle you just created and the original circle.
5) Now construct a line from these new points to the external point C. These are your tangent lines to the circle that intersect and an external point.
6) Select the TEXT tool from the 5th toolbar box, and type your name on the construction before you screenshot it for your assignment.