CIRCLES 2 Moody Mathematics. ANGLE PROPERTIES: Moody Mathematics Let’s review the methods for...
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Transcript of CIRCLES 2 Moody Mathematics. ANGLE PROPERTIES: Moody Mathematics Let’s review the methods for...
ANGLE ANGLE PROPERTIES:PROPERTIES:
Moody MathematicsMoody Mathematics
Let’s review the Let’s review the methods for finding methods for finding the arcs and the the arcs and the different kinds of different kinds of angles found in angles found in circles.circles.
Moody MathematicsMoody Mathematics
The measure of a minor arc is the same as…
…the measure of its central angle.
Moody MathematicsMoody Mathematics
The measure of an inscribed angle is…
…half the measure of its intercepted angle.
Moody MathematicsMoody Mathematics
The measure of an angle formed by a tangent and secant is …
…half the measure of its intercepted arc.
Moody MathematicsMoody Mathematics
The measure of one of the vertical angles formed by 2 intersecting chords
...is half the sum of the two intercepted arcs.
Moody MathematicsMoody Mathematics
The measure of an angle formed by 2 secants intersecting outside of a circle is…
…half the difference of the measures of its two intercepted arcs.
Moody MathematicsMoody Mathematics
The measure of an angle formed by 2 tangents intersecting outside of a circle is…
…half the difference of the measures of its two intercepted arcs.
PROPERTIES: PROPERTIES: Complete the Complete the theorem relating theorem relating the objects the objects pictured in each pictured in each frame.frame.
Moody MathematicsMoody Mathematics
Note: Note: Many Many of our theorems of our theorems begin the same begin the same way, “In the same way, “In the same circle, circle, or in or in congruent congruent circlescircles…”…”
Moody MathematicsMoody Mathematics
So: So: We will We will just start “In the just start “In the same circle*…” same circle*…” where the where the ** represents the represents the rest of the phrase. rest of the phrase.
Moody MathematicsMoody Mathematics
Moody MathematicsMoody Mathematics
In the same circle,* Congruent central angles...
...intercept congruent arcs.
Moody MathematicsMoody Mathematics
In the same circle,* Congruent Chords...
...intercept congruent arcs.
Moody MathematicsMoody Mathematics
Tangent segments from an exterior point to a circle…
...are congruent.
Moody MathematicsMoody Mathematics
The radius drawn to a tangent at the point of tangency…
...is perpendicular to the tangent.
Moody MathematicsMoody Mathematics
If a diameter (or radius) is perpendicular to a chord, then…
...it bisects the chord……and the arcs.
Moody MathematicsMoody Mathematics
In the same circle,* Congruent Chords...
...are equidistant from the center.
Moody MathematicsMoody Mathematics
Example: Given a circle of radius 5” and two 8” chords. Find their distance to the center.
5
4
4
2 2 24 5x 3x
x
Moody MathematicsMoody Mathematics
If two Inscribed angles intercept the same arc...
...then they are congruent.
Moody MathematicsMoody Mathematics
If an inscribed angle intercepts or is inscribed in a semicircle …
...then it is a right angle.
180
Moody MathematicsMoody Mathematics
If a quadrilateral is inscribed in a circle then each pair of opposite angles …
...must be supplementary.
(total 180o)
Moody MathematicsMoody Mathematics
If 2 chords intersect in a circle, the lengths of segments formed have the following relationship:
a b c d
a
b
c d
Moody MathematicsMoody Mathematics
If 2 secants intersect outside of a circle, their lengths are related by…
a b c d
a
c
bd
Moody MathematicsMoody Mathematics
If a secant and tangent intersect outside of a circle, their lengths are related by…
a a c d
a
c
d
Moody MathematicsMoody Mathematics
Example: Given
50
P
A
B
C
D
P
mAB
mBC
mABC
mADB
mACD
50
130
180
310
230
Moody MathematicsMoody Mathematics
Example: Given a circle of radius 13” and two 24” chords. Find their distance to the center.
1312
2 2 212 13x 5x
x12
Example: Of the following quadrilaterals, which can not always be inscribed in a circle?
A.Rectangle
B.Rhombus
C.Square
D.Isosceles Trapezoid
Moody MathematicsMoody Mathematics
Example: Regular Hexagon ABCDEF is inscribed in a circle. A B
C
DE
F
mACE 240