Math (final)

• Radius


  The distance from the center of the circle to its outer rim
• Chord


  A line segment whose endpoints are on a circle
• Diameter


  A chord that passes through the center of the circle. The length of the diameter is two times the length of a radius.
• Secant


  A line that intersects a circle in two points.
• Tangent


  A line that intersects a circle in exactly one point.
• Point of Tangency


  The point where a tangent line touches the circle
• Sector


  Made of the arc of the circle along with its two radii
• Segment


  Which is cut from the circle by a chord

  A line between two points on the circle
• Tangent Circles


  2 or more circles that intersect at one point
• Concentric Circles


  2 or more circles that have the same center, but different radii
• Congruent Circles


  2 or more circles with the same radius, but different centers
• The degree measure of the minor arc is equal to the measure of its central angle.
• The degree measure of the major arc is equal 360 minus the degree measure of its related minor arc.
• The degree measure of semicircle is 180.
• The measure of an inscribed angle is equal to one-half the measure of its intercepted arc.
• Theorem 115: The measure of an inscribed angle is equal to one-half the measure of its intercepted arc.
• Central angle is always equal to its intercepted arc 

  Inscribed angle is half of its intercepted arc.

  The name of the circle is determined by its center point.
• A common tangent is a line that is tangent to each of two coplanar
• Theorem 118: if two segments from the same external point are tangent to a circle, then two segments are congruent
• Pythagorean Theorem: c^2 + b^2 = a^2 + b^2
• The sum of the degrees of triangle is 180 degrees
• Theorem 120: If two secants intersect in the interior of a circle, then the measure of the angle formed is equal to one-half the sum of the measures of the intercepted arc
• Theorem 121: IF two secants intersect in the exterior of a circle, then the measure of the angle formed is one-half the positive difference of the measures of intercepted arcs.
• Theorem 122: the measure of an angle formed by a secant and a tangent intersecting at a point on the circle is one-half the measure of the intercepted arc
• Theorem 124: the measure of an angle formed by two tangents to the same circle is one-half the positive difference of the measures of the intercepted arc