See Problem 5.

Find the area of each circle in terms of π.

Find the area of each circle using an approximation of π. If necessary, round to the nearest tenth.

27. r = 7  ft r equals 7 ft
28. d = 8 . 3  m d equals 8 . 3 m
29. d = 24  cm d equals 24 , cm
30. r = 12  in. r equals 12 , in.

See Problem 6.

Find the area of the shaded region. All angles are right angles.

B Apply

Home Maintenance To determine how much of each item to buy, tell whether you need to know area or perimeter. Explain your choice.

34. wallpaper for a bedroom
35. crown molding for a ceiling
36. fencing for a backyard
37. paint for a basement floor
38. Think About a Plan A light-year unit describes the distance that one photon of light travels in one year. The Milky Way galaxy has a diameter of about 100,000 light-years. The distance to Earth from the center of the Milky Way galaxy is about 30,000 light-years. How many more light-years does a star on the outermost edge of the Milky Way travel in one full revolution around the galaxy compared to Earth?
    • What do you know about the shape of each orbital path?
    • Are you looking for circumference or area?
    • How do you compare the paths using algebraic expressions?
39. 1. What is the area of a square with sides 12 in. long? 1 ft long?
    2. How many square inches are in a square foot?

40. 1. Count squares below to find the area of the polygon outlined in blue.

       

    2. Use a formula to find the area of each square outlined in red.
    3. Writing How does the sum of your results in part (b) compare to your result in part (a)? Which postulate does this support?
41. The area of an 11-cm-wide rectangle is 176   cm 2 . 176 , cm squared , .  What is its length?
42. A square and a rectangle have equal areas. The rectangle is 64 cm by 81 cm. What is the perimeter of the square?

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