Download presentation

Presentation is loading. Please wait.

Published byBrendan Jefferson Modified over 4 years ago

1
Holt CA Course 1 9-4Circumference and Area MG2.1 Use formulas routinely for finding the perimeter and area of basic two- dimensional figures and the surface area and volume of basic three-dimensional figures, including rectangles, parallelograms, trapezoids, squares, triangles, circles, prisms, and cylinders. Also covered: MG3.2 California Standards

2
Holt CA Course 1 9-4Circumference and Area Radius Center Diameter Circumference The diameter d is twice the radius r. d = 2r The circumference of a circle is the distance around the circle.

3
Holt CA Course 1 9-4Circumference and Area

4
Holt CA Course 1 9-4Circumference and Area Remember! Pi () is an irrational number that is often approximated by the rational numbers 3.14 and. 22 7

5
Holt CA Course 1 9-4Circumference and Area Additional Example 1: Finding the Circumference of a Circle A. circle with a radius of 4 m C = 2r = 2(4) = 8m 25.1 m B. circle with a diameter of 3.3 ft C = d = (3.3) = 3.3ft 10.4 ft Find the circumference of each circle, both in terms of and to the nearest tenth. Use 3.14 for .

6
Holt CA Course 1 9-4Circumference and Area Check It Out! Example 1 A. circle with a radius of 8 cm C = 2r = 2(8) = 16cm 50.2 cm B. circle with a diameter of 4.25 in. C = d = (4.25) = 4.25in. 13.3 in. Find the circumference of each circle, both in terms of and to the nearest tenth. Use 3.14 for .

7
Holt CA Course 1 9-4Circumference and Area

8
Holt CA Course 1 9-4Circumference and Area Additional Example 2: Finding the Area of a Circle A = r 2 = (4 2 ) = 16in 2 50.2 in 2 A. circle with a radius of 4 in. Find the area of each circle, both in terms of and to the nearest tenth. Use 3.14 for . B. circle with a diameter of 3.3 m A = r 2 = (1.65 2 ) = 2.7225 m 2 8.5 m 2 d2d2 = 1.65

9
Holt CA Course 1 9-4Circumference and Area B. circle with a diameter of 2.2 ft A = r 2 = (1.1 2 ) = 1.21ft 2 3.8 ft 2 d2d2 = 1.1 Check It Out! Example 2 Find the area of each circle, both in terms of and to the nearest tenth. Use 3.14 for . A = r 2 = (8 2 ) = 64cm 2 201.0 cm 2 A. circle with a radius of 8 cm

10
Holt CA Course 1 9-4Circumference and Area Additional Example 3: Finding the Area and Circumference on a Coordinate Plane A = r 2 = (3 2 ) = 9units 2 28.3 units 2 C = d = (6) = 6units 18.8 units Graph the circle with center (–2, 1) that passes through (1, 1). Find the area and circumference, both in terms of and to the nearest tenth. Use 3.14 for

11
Holt CA Course 1 9-4Circumference and Area Check It Out! Example 3 x y A = r 2 = (4 2 ) (–2, 1) = 16units 2 50.2 units 2 C = d = (8) = 8units 25.1 units 4 (–2, 5) Graph the circle with center (–2, 1) that passes through (–2, 5). Find the area and circumference, both in terms of and to the nearest tenth. Use 3.14 for

12
Holt CA Course 1 9-4Circumference and Area Additional Example 4: Measurement Application C = d = (56) 176 ft (56) 22 7 22 7 A Ferris wheel has a diameter of 56 feet and makes 15 revolutions per ride. How far would someone travel during a ride? Use for . Find the circumference. 56 1 22 7 The distance is the circumference of the wheel times the number of revolutions, or about 176 15 = 2640 ft.

13
Holt CA Course 1 9-4Circumference and Area 12 3 6 9 Check It Out! Example 4 A second hand on a clock is 7 in. long. What is the distance it travels in one hour? Use for . 22 7 C = d = (14) (14) 22 7 Find the circumference. 44 in. The distance is the circumference of the clock times the number of revolutions, or about 44 60 = 2640 in. 14 1 22 7

Similar presentations

© 2019 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google