1. C IRCLES (G.11 A /10.6) OBJ: SWB INTRODUCED TO BASIC TERMINOLOGY OF C IRCLES. SWBAT FIND THE MEASURES OF CENTRAL ANGLES, ARCS, 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 )

2. P RACTICE : P ARTS OF CIRCLE C F E AB P Circle: ______P Radius: ____ Diameter: ____ Chord:____ Identify a special chord:____ Secant: ____ Minor Arc: ____ Major Arc: ____Central Angle: ____ Semicircle: ____ *** Foldable: “Important Parts of a Circle” Tangent line: _______Pt of tangency: _____ Sector : ____ Arc: ____ K

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

8. 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. 16 in Circle Foldable: “Central Angle”

10. T HM : I N 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:mABC = mAB + mBC

11. ARC: Is a part of a circle A) SEMI – CIRCLE (Half a circle) = 180° TRS is a semi-circle mTRS is 180° B) MINOR ARC: shorter than a semi-circle RS is a minor arcmRS = m ∠RPS 60° **** 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 mRTS = 360 – mRS ***The measure of a major arc is: 360 – the measure of its related minor arc.

12. D EFINITIONS 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.