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How Do You Find the Area of a Circle if You Know the Radius?

The radius of the circle is 7 inches. Find the area of the circle. Use 3.14 for π.

Summary

  1. 'A' represents the area of the circle
  2. 'π' is pi, an irrational number with a value of approximately 3.14
  3. 'r' is the radius, which is 7 inches here
  4. We plugged our information into the A=πr2 formula
  5. We get "A=153.86", which means the area is 153.86 inches squared!

Notes

    1. Remember, to find the area of the circle, you need to multiply pi by the radius squared
    2. A = πr2
    1. The radius, 'r', is 7 inches
    2. Since 'π' is an irrational number, we use its approximation of 3.14
    1. The radius, 'r', is 7 inches
    2. Since 'π' is an irrational number, we use its approximation of 3.14
    1. A = πr2
    2. Use the order of operations to solve for 'A'
    3. We first want to simplify the right side of the equation by squaring 7
    4. 72 = 49
    5. Multiply 3.14 by 49 to solve for the area of the circle
    6. 3.14(49) = 153.86
    7. Don't forget that the units will be inches squared!
    1. A = (3.14)(7)2 = (3.14)(49) = 153.86 in2