165 Lesson 6.5 The Circumference/Diameter Ratio circumference: the distance around a circle : the ratio of the circumference to the diameter of a circle. C-65 Circumference Conjecture If C is the circumference and d is the diamter of a circle, then there is a number such that C=. If d=2r, where r is the radius, then C=. Eample 1: If a circle has diameter 3.0 meters, what is the circumference? Give the eact answer in terms of and rounded to the nearest 0.1 m. Eample 2: If a circle has circumference 12 what is the radius? meters, Oct 24 3:14 PM 1
165 Lesson 6.5 The Circumference/Diameter Ratio circumference: the distance around a circle : the ratio of the circumference to the diameter of a circle. C-65 Circumference Conjecture If C is the circumference and d is the diamter of a circle, then there is a number such that C=. If d=2r, where r is the radius, then C=. Eample 1: If a circle has diameter 3.0 meters, what is the circumference? Give the eact answer in terms of and rounded to the nearest 0.1 m. Eample 2: If a circle has circumference 12 what is the radius? meters, Oct 24 3:14 PM 2
Lesson 6.6 Around the World-application problems Eample: If the diameter of the Earth is 8000 miles, find the average speed in miles per hour needed to circumnavigate the earth about the equator in 80 days. To find the speed (rate) we need the distance and the time. D=rt Find the total distance Speed (rate) = total distance total time How do we change it from miles per day to miles per hour? Eample: Alfonzo s Pizzeria bakes olive pieces in the outer crust of its 20 inch (diameter) pizza. There is at least two olive pieces per inch of crust. How many olive pieces will you get in one slice of pizza? Assume the pizza is cut into 8 slices. Find the circumference of the pizza. How many inches in one slice? How many olive pieces? Eample: To use the machine, you turn the crank, which turns the pulley wheel, which winds the rope and lifts the bo. Through how many rotations must you turn the crank to lift the bo 10 feet? Oct 24 3:15 PM 3
Lesson 6.6 Around the World application problems Eample: If the diameter of the Earth is 8000 miles, find the average speed in miles per hour needed to circumnavigate the earth about the equator in 80 days. To find the speed (rate) we need the distance and the time. D=rt Find the total distance Speed (rate) = total distance total time How do we change it from miles per day to miles per hour? Eample: Alfonzo s Pizzeria bakes olive pieces in the outer crust of its 20 inch (diameter) pizza. There is at least two olive pieces per inch of crust. How many olive pieces will you get in one slice of pizza? Assume the pizza is cut into 8 slices. Find the circumference of the pizza. How many inches in one slice? How many olive pieces? Eample: To use the machine, you turn the crank, which turns the pulley wheel, which winds the rope and lifts the bo. Through how many rotations must you turn the crank to lift the bo 10 feet? Oct 24 3:15 PM 4
168 Lesson 6.6 Around the World-application problems Eample: If the diameter of the Earth is 8000 miles, find the average speed in miles per hour needed to circumnavigate the earth about the equator in 80 days. To find the speed (rate) we need the distance and the time. D=rt Find the total distance Speed (rate) = total distance total time How do we change it from miles per day to miles per hour? Eample: Alfonzo s Pizzeria bakes olive pieces in the outer crust of its 20 inch (diameter) pizza. There is at least two olive pieces per inch of crust. How many olive pieces will you get in one slice of pizza? Assume the pizza is cut into 8 slices. Find the circumference of the pizza. How many inches in one slice? How many olive pieces? Eample: To use the machine, you turn the crank, which turns the pulley wheel, which winds the rope and lifts the bo. Through how many rotations must you turn the crank to lift the bo 10 feet? Oct 24 3:15 PM 5
DO 6.2 Oct 24 3:14 PM 6
DO 6.2 Oct 24 3:14 PM 7
Oct 24 3:16 PM 8