Radius & Diameter
Which equation correctly represents the relationship between a circle’s diameter (d) and its radius (r)?
d=2r
The distance around the circle is known as:
circumference
Which formula is used to calculate the area of a circle?
A=πr2
A painter wants to know how much paint is needed to cover the top of a circular table. Which measurement should they calculate?
Area
What is the area of a circle pancake with a radius of 9?
a pancake with butter on top. yummm:)
A bicycle wheel has a radius of 13 inches. What is the diameter of the wheel?
26 inches
Using the approximation π≈3, what is the estimated circumference of a circle with a diameter of 10 cm?
30cm
A circular field is set inside a square with an 800 m side length. Which is the most reasonable estimate for the field’s area?
500,000 m2
If a bike wheel has a circumference of 5 feet, how far does the bike travel after 15 complete rotations?
75 feet
If all the students in the seventh grade joined hands to make a circle. What would the circumfrence be with a diameter of 29?
91.06
Circle A has a diameter of 9 cm. What is its radius?
4.5 cm.
A dartboard has a diameter of 18 inches. Using π≈3.14, what is its approximate circumference?
56.52 inches
What is the exact area, in terms of π, of a circle with a radius of 10 feet?
100pi sq ft
In a stained-glass project, clear glass costs $2 per square foot. If a design uses 9.42 square feet of clear glass, what is the approximate cost for that glass?
$18.84
What is the area of a square with a side of 4?
16
A wagon wheel has a diameter of 3 feet. Which measurement represents the distance from the center of the wheel to the outer edge?
1.5 ft
A circle has a circumference of approximately 44 cm. Which of the following is the best estimate for its diameter? (Use π≈22/7)
14cm
Circle A has a diameter of 20 inches and an area of about 300 in2. If Circle B has a diameter of 60 inches (3 times larger), its area will be approximately:
2,700cm2
If a stained-glass window design is enlarged by a scale factor of 3, by what factor does the total area of the glass increase?
9
What is the area in total of three pieces of fruit with a diameter of 2 inches, 4 inches, and 7 inches?
216.66
If a line segment goes from one edge of a circle to the other and passes through the center, it is called the:
Diameter
A wooden block has a face that is a 9 cm by 4.5 cm rectangle with a semicircle cut out of the bottom (diameter of 5 cm). What is the total length of the curved edge of the cutout?
2.5pi cm
A square has a side length of 10 ft. A circle with a diameter of 10 ft is placed inside. Using π≈3.14, what is the area of the square not covered by the circle?
21.5 sq ft
A car wheel rotates once per second. If its circumference is 65 inches, how far does the car travel in one minute?
3,900 inches
What is the perimeter of the square with a side of 10?
40