Prime Time Circle the seven prime numbers that, when added together, equal 75. 3, 11, 14, 13, 5, 17, 12, 6, 19, 23, 7, 9 Remember a prime number is a number that has only two factors, 1 and itself. 2 is prime : 1x2

Prime Time Solution 3 + 5 + 7 + 11 + 13 + 17 + 19 = 75

Area of Circles Lesson 11-6

Review of Circles r d The radius of a circle is half of the diameter. Divide the diameter by 2 to get the radius.

Area of a Circle Area = r² The area of a circle equals the product of pi () and the square of its radius. r Area = r²

Find the Area of the Circle Round the answer to the nearest tenth. Area = r² A = (4²) A = (16) A = 50.3 cm² 4 cm

Find the Area of the Circle Round the answer to the nearest tenth. Area = r² A = (8²) A = (64) A = 201.1 in² 8 in

Find the Area of the Circle Round the answer to the nearest tenth. Area = r² A = (5.5²) A = (30.25) A = 95.0 ft² 11 ft Use the diameter to find the radius. 11 ÷ 2 = 5.5 Radius = 5.5 ft

Find the Area of the Circle Round the answer to the nearest tenth. Area = r² A = (3.25²) A = (10.5625) A = 33.2 m² 6.5 m Use the diameter to find the radius. 6.5 ÷ 2 = 3.25 Radius = 3.25 m

Find the area to the nearest tenth. 25.6 m 9.8 in Area = r² A = (12.8²) A = (163.84) A = 514.7 m² Area = r² A = (9.8²) A = (96.04) A = 301.7 in²

Area of a Semi-Circle Area = r² A = (13²) A = (169) A = 530.9 ft² 530.9 ft² is the area of the whole circle. How can you find the area of half the circle. Divide the area by 2. A semi- circle is half of a circle. Answer: 265.5 ft²

Homework Lesson 11-6 # 2-16 even TEST: On Friday, lesson 11-5 (area of triangles and trapezoids), lesson 11-6 (area of circles), and lesson 11-7 (we will complete this tomorrow)