Tangent - A line that intersects a circle in exactly one point. The point where the line intersects the circle is called the point of tangency. A line that intersects a circle in two points. Concentric Circles circles with the same center but different radii Interior of a circle any point whose distance to the center of the circle is less than the circles radius is in the interior. F is in the interior of the circle .
G is in the exterior of the circle.
Congruent Circles- circles whose radii are the same length. Introduce radii AB and AC, these are congruent because radii of a circle are congruent. If the angles formed at D are both right angles because of the definition of perpendicular, the triangles ADB and ADC are both right triangles. Although we will learn this later on it is easy to prove additonally if the central angles in the circle are congruent, then their intercepted arcs are congruent. If the radius of circle J is 13 and chord MK is 5 cm from the center of the circle, find the length of the chord.