CIRCLES G 11 A10 6 OBJ SWB INTRODUCED

CIRCLES (G. 11 A/10. 6) OBJ: SWB INTRODUCED TO BASIC TERMINOLOGY OFCIRCLES. SWBAT FIND THE MEASURES OF CENTRAL ANGLES, ARC LENGTHS AND CIRCUMFERENCE (G. 11 B, C) WU: SOL questions G. 7 -GRADED!!!! **hw/hw log/wkb p. 271 circle foldable/Storybook “Circles” Homework (day 53): wkb p. 271 -272 (omit 18, 23 -25) Bring Graph Paper to class! Pearsonsuccess. net (due Friday)

PRACTICE: PARTS OF CIRCLE K Circle: ______ P Radius: ____ C Diameter: ____ Chord: ____ Secant: ____ Identify a special chord: ____ A B P Arc: ____ Minor Arc: ____ Major Arc: ____ Semicircle: ____ E Tangent line: _______ Central Angle: ____ Sector : ____ Pt of tangency: _____ F *** Foldable: “Important Parts of a Circle”

GEOMETRIC FIGURES CAN HELP YOU FIND THE CIRCUMFERENCE OF A CIRCLE Is the rectangle inscribed or circumscribed in the circle? Find the exact circumference of P. The diameter = _____ the exact circumference = _______ the approximate circumference = _______ (to the nearest tenth) 5 12 P

What word refers to the outside of a polygon? What word refers to the distance around a circle? Another way to measure an arc is by its length. Since an arch is a part of a circle, its length is PART of the circumference…. . called the ARC LENGTH Find the length of XY. Leave your answer in term of π. Circle Foldable: “Central Angle” 16 in

THM: IN THE SAME OR CONGRUENT CIRCLES, TWO ARCS ARE CONGRUENT IFF THEIR CORRESPONDING ANGLES ARE CONGRUENT. Adjacent Arcs: two arcs in the same circle that have exactly one point in common. ***You can add the measures of adjacent arc just like you add the measures of adjacent angles. Arc Addition Postulate: m. ABC = m. AB + m. BC

ARC: Is a part of a circle A) SEMI – CIRCLE (Half a circle) = 180° TRS is a semi-circle m. TRS is 180° B) MINOR ARC: shorter than a semi-circle RS is a minor arc m. RS = m∠RPS **** The measure of a minor arc = the measure of its central angle. C) Major Arc: Larger than a semi-circle RTS is a major arc m. RTS = 360 – m. RS ***The measure of a major arc is: 360 – the measure of its related minor arc. 60°

DEFINITIONS Radius: is a segment w/one endpoint at the center of the circle and the other endpoint on the circle. (All radii of a circle are congruent) Chords: are segments that have both their endpoints on the circle. (from one side of the circle to the other. ) Diameter: a chord that goes through the center of a circle.