11.5 Area of Circles and Sectors Theorem The equation for the Area of a Circle Area equals radius squared times pi. Ar 2 9 Theorem The equation for the Area of a Circle Area equals radius squared times pi. Ar A 9 2 2 9 A 81 Definition of a Circle Sector A circle sector is a fraction of the circle enclosed by two radii and an arc. Minor Sector Major Sector Pac Man Theorem The Equation for the Area of a Sector Sector 360 r 2 135 11 Theorem The Equation for the Area of a Sector Sector 360 r 2 135 2 11 Sector 360 3 Sector 121 8 45.375 135 11 Find the Radius The Sector Area is 15 Central Angle 150 Sector 150 360 r 150 2 r 15 360 2 Find the Radius The Sector Area is 15 Central Angle 150 Sector 150 360 r 150 2 r 15 360 15 5 2 r 12 2 Find the Radius The Sector Area is 15 Central Angle 150 Sector 150 r 2 360 150 2 r 15 360 5 15 r 2 12 r2 12 15 36 5 r 2 36 r 2 36 Find the Radius The Sector Area is 15 Central Angle 150 Sector 150 15 15 360 r 150 2 r 360 5 2 r 12 2 12 r 2 15 36 5 r 2 36 r 2 36 r 6 Find the Shaded Area Hint : find the Area of the Circle – the Area of the triangle 60 4 4 60 60 4 Find the Shaded Area Hint : find the Area of the Circle – the Area of the triangle 60 4 60 4 2 2 4 60 2 3 2x x 30 2 x 3 2 2x 2 3 2x r 4 3 Find the Shaded Area Hint : find the Area of the Circle – the Area of the triangle 16 4 Area of the circle 3 3 60 4 60 4 2 2 4 60 Area of triagnle 1 2 A 4 3 4 3 4 1 2 3 side 4 Find the Shaded Area Hint : find the Area of the Circle – the Area of the triangle 16 4 Area of the circle 3 3 60 4 60 4 2 2 4 60 Area of triagnle 1 2 3 side 4 1 2 A 4 3 4 3 4 16 RED area 4 3 3 Homework Page 695-698 # 10 – 28 even, 31 – 37, 40, 41, 43 - 44