Half the circumference Notes Over 10 - 3 Area of Circles Parallelogram A = b h radius Half the circumference

Notes Over 10 - 3 Area of Circles A = p r2 A = p r2 A = 3.14 ( 3 )2 Find the area of each figure. 1. 3 in 20 m 2. A = p r2 A = p r2 A = 3.14 ( 3 )2 A = 3.14 ( 10 )2 A = 3.14 ( 9 ) A = 3.14 ( 100 ) A = 28 in2 A = 314 m2

Notes Over 10 - 3 Area of Circles A = 12 ( 12 ) A = 144 cm2 Find the area of each figure. 12 cm 3. 12 cm A = 12 ( 12 ) A = 144 cm2

Pg 517 10 – 3 #1 – 9, 10 – 27 A = p r2 A = p 32 A = p r2 A = 9 p in2 Find the area of each circle. Give an exact area and an approximate area to the nearest square unit. 1. r = 3 ft 2. d = 10 m A = p r2 r = 5 m A = p 32 A = p r2 A = 9 p in2 A = p 52 A = 25 p m2 A = 3.14 ( 9 ) A = 3.14 ( 25 ) A = 28 in2 A = 79 m2

Pg 517 10 – 3 #1 – 9, 10 – 27 Find the area of each circle. Give an exact area and an approximate area to the nearest square unit. 3. r = 20 cm 4. 12 ft A = p r2 A = p 202 A = 400 p cm2 A = 3.14 ( 400 ) A = p r2 = p 122 = 144 p ft2 A = 1256 cm2 A = 3.14 ( 144 ) A = 452 ft2

Pg 517 10 – 3 #1 – 9, 10 – 27 Find the area of each circle. Give an exact area and an approximate area to the nearest square unit. 16 m 5. 60 cm 6. A = p r2 = p 82 A = p r2 = p 302 = 64 p m2 = 900 p cm2 A = 3.14 ( 64 ) A = 3.14 ( 900 ) A = 201 m2 A = 2,826 cm2

Pg 517 10 – 3 #1 – 9, 10 – 27 Find the area of each figure to the nearest square unit. 7. 10 in 3.5 in 7 in + 1/2p r2 = 70 + 1/2p 3.52 A = 70 + ½ (3.14) ( 12.25 ) A = 70 + 19.2325 = 89 in2

Pg 517 10 – 3 #1 – 9, 10 – 27 Find the area of each figure to the nearest square unit. 8. 40 yd 40 yd 40 yd + p r2 = 1600 + p 202 A = 1600 + (3.14) ( 400 ) A = 1600 + 1256 = 2856 in2

Circle Pg 517 10 – 3 #1 – 9, 10 – 27 A = p r2 A = (2) (2) A = p 22 9. Which has a greater area, a circle with radius 2 m or a square with side length 2 m? Explain. 2 m 2 m A = p r2 A = (2) (2) A = p 22 A = 4 in2 A = (3.14) ( 4 ) Circle A = 12.56 in2

Pg 517 10 – 3 #1 – 9, 10 – 27