Circle Circumference and Area Formulas Practice
Use radius, diameter, pi, circumference, and area
Circle Circumference and Area Formulas Practice
Use radius, diameter, pi, circumference, and area
Math - Grade 6-8
- 1
A circle has a radius of 6 cm. Find its circumference using 3.14 for π.
Use C = 2πr because the radius is given.
The circumference is 37.68 cm because C = 2πr = 2 × 3.14 × 6 = 37.68. - 2
A circle has a diameter of 14 inches. Find its circumference using 3.14 for π.
The circumference is 43.96 inches because C = πd = 3.14 × 14 = 43.96. - 3
A circle has a radius of 5 meters. Find its area using 3.14 for π.
Square the radius before multiplying by 3.14.
The area is 78.5 square meters because A = πr² = 3.14 × 5² = 3.14 × 25 = 78.5. - 4
A circular table has a diameter of 8 feet. Find the area of the tabletop using 3.14 for π.
First find the radius by dividing the diameter by 2.
The area is 50.24 square feet. The radius is half the diameter, so r = 4 feet, and A = 3.14 × 4² = 50.24. - 5
A bicycle wheel has a radius of 13 inches. How far does the wheel travel in one full rotation? Use 3.14 for π.
The wheel travels 81.64 inches in one full rotation because one rotation is the circumference, and C = 2 × 3.14 × 13 = 81.64. - 6
A circular garden has a radius of 9 yards. Find its area using 3.14 for π.
The units for area are square units.
The area is 254.34 square yards because A = πr² = 3.14 × 9² = 3.14 × 81 = 254.34. - 7
The circumference of a circle is 31.4 cm. Find the diameter using 3.14 for π.
Use C = πd, then divide the circumference by π.
The diameter is 10 cm because d = C ÷ π = 31.4 ÷ 3.14 = 10. - 8
The circumference of a circle is 50.24 feet. Find the radius using 3.14 for π.
The radius is 8 feet because C = 2πr, so r = C ÷ 2π = 50.24 ÷ 6.28 = 8. - 9
A circular rug has a diameter of 12 feet. Find both the circumference and the area using 3.14 for π.
Use the diameter for circumference, then divide it by 2 to find the radius for area.
The circumference is 37.68 feet because C = 3.14 × 12 = 37.68. The radius is 6 feet, so the area is 113.04 square feet because A = 3.14 × 6² = 113.04. - 10
Two circles both have radius 4 cm. One student says the circumference is 25.12 cm, and another student says the area is 50.24 square cm. Are both students correct? Explain.
Both students are correct. The circumference is C = 2 × 3.14 × 4 = 25.12 cm, and the area is A = 3.14 × 4² = 50.24 square cm. - 11
A circular pond has an area of 153.86 square meters. The radius is 7 meters. Check whether the area is correct using 3.14 for π.
Substitute 7 for r in A = πr².
The area is correct because A = πr² = 3.14 × 7² = 3.14 × 49 = 153.86 square meters. - 12
A track is shaped like a circle with a diameter of 60 meters. A runner completes 3 full laps. How many meters does the runner travel? Use 3.14 for π.
The runner travels 565.2 meters. One lap is the circumference, C = 3.14 × 60 = 188.4 meters, and 3 laps is 188.4 × 3 = 565.2 meters.