Monday December 16

Test Friday 

Analytic Geometry UNIT QUESTION: What special properties are found with the parts of a circle? Standard: MM2G1, MM2G2 Today’s Question: How are central angles different from inscribed angles? Standard: MM2G3.b

Parts of a Circle Circle – set of all points _________ from a given point called the _____ of the circle. equidistant C center Symbol: C

CHORD: A segment whose endpoints are on the circle

Distance across the circle through its center Diameter DIAMETER: Distance across the circle through its center P Also known as the longest chord.

Radius RADIUS: Distance from the center to point on circle P

D = 24 32 12 r = ? 16 r = 4.5 6 D = 12 9

Use P to determine whether each statement is true or false. Q R T S True: thumbs up False: thumbs down

SECANT sounds like second Secant Line: intersects the circle at exactly TWO points SECANT sounds like second

a LINE that intersects the circle exactly ONE time Tangent Line: a LINE that intersects the circle exactly ONE time Forms a 90°angle

Secant Radius Diameter Chord Tangent Name the term that best describes the notation. Secant Radius Diameter Chord Tangent

Arc Length A portion of the circumference of the circle – as if you used a ruler to measure the length A B

THINGS TO REMEMBER: A circle has 360 degrees A semicircle has 180 degrees Vertical Angles are Equal Linear Pairs are Supplementary

Central Angle : vertex is at the center of the circle P C B APB is a Central Angle

Case I: Vertex is AT the center P C B

Semicircle: An Arc that equals 180° To name: use 3 letters E D EDF P F

Central Angle : vertex is at the center of the circle Major Arc Minor Arc More than 180° Less than 180° ACB P AB C B

measure of an arc = measure of central angle 96 Q m AB = 96° B C m ACB = 264° m AE = 2x + 14 Find x. x = 35