1. 10-3: Arcs and Chords

2. Arcs and Chords
The endpoints of a chord are also the endpoints of an arc.
In a circle, if two minor arcs are congruent, then their chords must be congruent as well.
In the following figures are arc AB and arc CD congruent?
EX1: Quad ABDC is a rectangle. EX2:

3. Circles and Polygons The inscribed shape is on the inside.
The circumscribed shape is on the outside.

4. Circumscribed or Inscribed?
EX1: Triangle LMN is ______________ in circle O.
EX2: Circle O is __________________ about triangle LMN.
EX3: Circle P is __________________ about the polygon.
EX4: Octogon QRSTUVWX is an _____________________.

5. Determine the measure of each arc.
EX1: EX 2:

6. Diameters and Chords
If a diameter (or radius) is perpendicular to a chord, then it bisects the chord and its arc.

7. EX 1: Find AY.
EX 2: Find AD.
EX 3: Find YD.
EX 4: Find DB.
EX5: Find AB.

8. Example 3 on p. 538 in textbook
Circle O has a radius of 13 in. Radius OB is perpendicular to chord CD, which is 24 in. long.
A. If mCD = 134, find
mCB.
B. Find OX.

9. Additional. Ex. 3 from TE textbook
Circle W has a radius of 10 cm. Radius WL
is perpendicular to chord HK,
which is 16 cm long.
If mHL = 53, find mMK.
Find JL

10. If circle A has a radius of 5, CD=4, and AF=3, find AC, BD, and EG.
Two chords are congruent if and only if they are equidistant from the center.

11. A chord of a circle is 48cm long and is 10 cm
A chord of a circle is 48cm long and is 10 cm. from the center of the circle. Find the radius.

12. Assignment Regular: p. 540 + 541: 11-35odd, 40-41 W.S. 10-3: 1-14
Honors : p : 11-35, 40-41