A circular pool has a radius of 20 feet. What is the area of the pool? Use 3.14 for π.
2 answers:
The formula for area is
However, we are substituting pi for 3.14, so in this case the formula is 3.14×r^2
Here's a non-calculator method:
When r=20, A=3.14×20^2
20^2=400
Let's convert 3.14 into an integer by multiplying by 100, so we can deal with the numbers more easily:
314×400=(314×400)×100=125600
Now divide by 100 to put the decimal places of 3.14 back:
125600÷100=1256
If you noticed, we could have just cancelled out the decimal places in the 3.14 by dividing 400 by 100, meaning we could have just done 314×4
Besides this, the area of the pool is 1256ft^2
However, we are substituting pi for 3.14, so in this case the formula is 3.14×r^2
Here's a non-calculator method:
When r=20, A=3.14×20^2
20^2=400
Let's convert 3.14 into an integer by multiplying by 100, so we can deal with the numbers more easily:
314×400=(314×400)×100=125600
Now divide by 100 to put the decimal places of 3.14 back:
125600÷100=1256
If you noticed, we could have just cancelled out the decimal places in the 3.14 by dividing 400 by 100, meaning we could have just done 314×4
Besides this, the area of the pool is 1256ft^2
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