290 likes | 415 Views
Core-Plus Mathematics Project Home Math Department Home SAHS Home. Circles. Vocabulary And Properties. Circle. A set of all points in a plane at a given distance from a given point in the plane. Radius. A segment from a point on the circle to the center of the circle. Congruent Circles.
E N D
Core-Plus Mathematics Project Home Math Department Home SAHS Home Circles Vocabulary And Properties
Circle A set of all points in a plane at a given distance from a given point in the plane. .
Radius A segment from a point on the circle to the center of the circle.
Congruent Circles Two circles whose radii have the same measure. R=3 cm R=3 cm
Concentric Circles Two or more circles that share the same center. .
Chord Is a segment whose endpoints lie on the circle. B A D C
Diameter A chord passing through the center of a circle. J I
Secant A line that contains a chord.
Tangent A line in the plane of the circle that intersects the circle in exactly one point.
Semicircle A semicircle is an arc of a circle whose endpoints are the endpoints of the diameter. Is a semicircle
Minor Arc An arc of a circle that is smaller than a semicircle. The minor arc is AP (clockwise) or PD (clockwise). P D A
Major Arc An arc of a circle that is larger than a semicircle. The major arc would be PA (clockwise) or DP (counter clockwise). P A D
Inscribed Angle An angle whose vertex lies on a circle and whose sides contain chords of a circle. A C B D
Central Angle An angle whose vertex is the center of the circle. A B O
Properties of Circles The measure of a central angle is two times the measure of the angle that subtends the same arc.
If the m<C is 55, then the m<O is 110. Both angle C and angle O subtend the same arc, AB. Example B A O C
Property #2 Angles inscribed in the same arc are congruent.
The m<AQB and the m<APB are congruent because they both inscribe arc AB. The m<QAP and m<QBP would be congruent because they inscribe arc QP. Example A B Q P
Property #3 Every angle inscribed in a semicircle is an right angle.
Each of the three angles inscribed in the semicircle is a right angle. Example C D B Angle B, C, and D are all 90 degree angles. A E
Property #4 The opposite angles of a quadrilateral inscribed in a circle are supplementary.
Example The measure of angle D + angle B=180 The measure of angle C+angle A=180 B 65 A 70 110 C 115 D
Property #5 Parallel lines intercept congruent arcs on a circle.
Example Arc AB is congruent to Arc CD A B D C
Formulas What are the two formulas for finding circumference? C= C=
Answer C=2 pi r C=d pi
Area of a circle A=?
Answer A=radius square times pi
The End Core-Plus Mathematics Project Home Math Department Home SAHS Home