Math 12AP – Reviewing of
Circle Geometry
Topics
Chord Properties
- Congruent chords are located
the same distance away from the centre of a circle.
- The perpendicular bisector of a
chord passes through the centre of a circle.
- The longest chord in a circle
is the diameter.
Logic Statements
- An “if and only if” statement (iff) can be made if the original
statement and the converse of that statement are both true.
Coordinate Geometry
- Parallel lines have the same
slope and perpendicular lines have opposite reciprocal slopes
- Pythagorean Theorem

- Distance Formula

- Midpoint Formula

- Know how to find the centre of
a circle given the endpoints of two chords on the circle.
- Know how to find the area of a
triangle given the vertices of a triangle by finding an altitude.
Congruent Triangles and Proofs
- SSS, SAS, ASA, SAA and HL
Triangle Congruence Theorems
- Two column proofs. Justifications for statements in a proof
might include shared side, segment addition, supplementary or
complementary angles, x-theorem
(vertical angles are congruent), z-theorem
(opposite interior angles are congruent), definitions of midpoint,
isosceles, or perpendicular.
Central and Inscribed Angle Properties
- The measure of a central angle
is equal to the measure of the arc it intercepts.
- An inscribed angle is half the
measure of the central angle subtended by the same arc.
- All inscribed angles subtended
by the same arc are equal.
- An angle inscribed in a
semi-circle measures 90°.
The Equation of a Circle
- Standard Form is
for a circle with
centre (h, k) and a radius of r.
- General Form is

- Transformational Form is
for a circle with
centre (h, k) and a radius of r.
- Mapping rules as
transformations of the unit circle

- Graphing circles from their
equation and stating the domain and range
The Equation of an Ellipse
- An ellipse is a circle that has
been stretched horizontally and vertically by different amounts.
- Transformational form is
for an ellipse
with centre (h, k).
2a is the length of the
horizontal axis of the ellipse and 2b
is the length of the vertical axis.
- The longer axis of an ellipse
is called the major axis, and the shorter axis is called the minor axis.