Finding the Area of Circles Using Pi

What is the formula used to calculate the area of a circle?

• A = πr²

• A = πr

• A = 2πr

• A = πd

If the radius of a circle is 3, what is the value of r²?

• 15

• 9

• 6

• 12

How do you calculate the area when the radius is known?

• None of the above

• Multiply π by the diameter

• Square the radius and multiply by π

• Double the radius and multiply by π

What is the result of multiplying 3.14 by 9 in the context of area calculation?

• 30.26

• 29.26

• 27.26

• 28.26

When given the diameter of a circle as 20, what should be used as the radius for area calculation?

• 20

• 10

• 30

• 40

What is the correct way to find the radius if the diameter is provided?

• Square the diameter

• Use the diameter as is

• Multiply the diameter by 2

• Divide the diameter by 2

What is the area of a circle when the radius is 10?

• 314 cm²

• 214 cm²

• 414 cm²

• 114 cm²

How do you adjust the decimal place when multiplying π by 100?

• Move the decimal two places to the left

• Move the decimal two places to the right

• No adjustment needed

• Move the decimal three places to the right

What is the area of a circle if the radius squared is 100 and π is approximated as 3.14?

• 314 cm²

• 214 cm²

• 514 cm²

• 114 cm²