Worksheet

Parts of a circle: radius, diameter, circumference and area

Grade 7 Math Worksheet - Challenge Me

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Circle the best answer, or write your answer on the line.

  1. A round garden bed is 31.4 m around. How many square meters of soil does Bo need to cover it? Use 3.14 for π.

  2. A round rug is 94.2 cm around. What is its area in square centimeters, Esme? Use 3.14 for π.

  3. A round trampoline mat is 125.6 cm around. Jun wants its area in square centimeters. Use 3.14 for π.

  4. A track has two straights of 85 m and two curved ends that together make a circle 30 m across. Kira runs 3 laps. How far? Use 3.14 for π.

  5. A track has two straights of 75 m and two curved ends that together make a circle 40 m across. Luz runs 4 laps. How far? Use 3.14 for π.

  6. A track has two straights of 60 m and two curved ends that together make a circle 36 m across. Milo runs 2 laps. How far? Use 3.14 for π.

  7. A track has two straights of 100 m and two curved ends that together make a circle 50 m across. Noah runs 5 laps. How far? Use 3.14 for π.

  8. One round pond has a radius of 3 m. Another has a radius of 6 m. How do the second pond's distance around and area compare with the first's, Pia?

    • Its distance around is 4 times as long and its area is 2 times as big.
    • Both are 2 times as much, because the radius is 2 times as big.
    • Its distance around is 2 times as long and its area is 4 times as big.
    • Both are 4 times as much, because 6 × 6 is 4 times as big as 3 × 3.

  9. A 12-inch pizza (across) and a 6-inch pizza (across) have the same thickness of dough. How much more dough does the 12-inch pizza need, Ren?

    • 2 times as much, because the distance across is 2 times as big.
    • 6 times as much, because 12 − 6 = 6 more inches across the pizza.
    • 3.14 times as much, because circle comparisons use the number π.
    • 4 times as much, because its area is 2 × 2 = 4 times as big.

  10. Tala cuts a circle into thin wedges and lays them point up, point down into a near-rectangle. Its width is half the circumference and its height is the radius. Which area rule follows?

    • Area = circumference × radius = 2πr × r = 2πr²
    • Area = ½ × circumference × radius = ½ × 2πr × r = πr²
    • Area = ½ × circumference × diameter = ½ × 2πr × 2r = 2πr²
    • Area = circumference + radius = 2πr + r
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Parts of a circle: radius, diameter, circumference and area

Answer Key - Grade 7 Math Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

  1. A round garden bed is 31.4 m around. How many square meters of soil does Bo need to cover it? Use 3.14 for π.

    78.5 m²

  2. A round rug is 94.2 cm around. What is its area in square centimeters, Esme? Use 3.14 for π.

    706.5 cm²

  3. A round trampoline mat is 125.6 cm around. Jun wants its area in square centimeters. Use 3.14 for π.

    1256 cm²

  4. A track has two straights of 85 m and two curved ends that together make a circle 30 m across. Kira runs 3 laps. How far? Use 3.14 for π.

    792.6 m

  5. A track has two straights of 75 m and two curved ends that together make a circle 40 m across. Luz runs 4 laps. How far? Use 3.14 for π.

    1102.4 m

  6. A track has two straights of 60 m and two curved ends that together make a circle 36 m across. Milo runs 2 laps. How far? Use 3.14 for π.

    466.08 m

  7. A track has two straights of 100 m and two curved ends that together make a circle 50 m across. Noah runs 5 laps. How far? Use 3.14 for π.

    1785 m

  8. One round pond has a radius of 3 m. Another has a radius of 6 m. How do the second pond's distance around and area compare with the first's, Pia?

    • Its distance around is 4 times as long and its area is 2 times as big.
    • Both are 2 times as much, because the radius is 2 times as big.
    • Its distance around is 2 times as long and its area is 4 times as big.
    • Both are 4 times as much, because 6 × 6 is 4 times as big as 3 × 3.

  9. A 12-inch pizza (across) and a 6-inch pizza (across) have the same thickness of dough. How much more dough does the 12-inch pizza need, Ren?

    • 2 times as much, because the distance across is 2 times as big.
    • 6 times as much, because 12 − 6 = 6 more inches across the pizza.
    • 3.14 times as much, because circle comparisons use the number π.
    • 4 times as much, because its area is 2 × 2 = 4 times as big.

  10. Tala cuts a circle into thin wedges and lays them point up, point down into a near-rectangle. Its width is half the circumference and its height is the radius. Which area rule follows?

    • Area = circumference × radius = 2πr × r = 2πr²
    • Area = ½ × circumference × radius = ½ × 2πr × r = πr²
    • Area = ½ × circumference × diameter = ½ × 2πr × 2r = 2πr²
    • Area = circumference + radius = 2πr + r