Question

What is the area of a circle with a diameter of 20 inches if

`\pi`
=3.1415​

Answer 1

The area of a circle with a 20-inch diameter is found using the formula A = πr². The radius is half the diameter, so the radius is 10 inches. Using π as 3.1415, the calculated area is approximately 310 inches² to two significant figures.

Step-by-step explanation:

To find the area of a circle with a diameter of 20 inches using π (pi) as 3.1415, you can use the formula A = πr². First, you must find the radius (r) of the circle, which is half the diameter. Therefore, the radius is 10 inches (20 inches / 2).

Now, you can plug the radius into the formula:

A = πr² = 3.1415 × (10 inches)²

A = 3.1415 × 100 inches²

A = 314.15 inches²

Using two significant figures, because that is the precision of the diameter provided, the area of the circle is approximately 310 inches².

Answer 2

$\sf\underline\bold\blue{Information\:given\:in\:the\:question:}$

• π =
  `\sf{ 3.1415}`
• $\sf{Diameter = 20inches}$

$\space$

$\sf\underline\bold\blue{What\:we\:have\:to\:find?}$

• $\sf{Area\:of\:the\:circle.}$

$\space$

$\sf\underline\bold\blue{Answer:}$

• $\sf\small{Area\:of\:the\:circle\:is : 314.15}$

$\space$

$\sf\underline\bold\blue{Calculations:}$

Here we have the value of the circle's diameter that is 20inches. So, first we have to calculate the radius of the circle using the formula :

$\mapsto$ $\sf\bold{Radius=}$ $\sf\dfrac{Diameter}{2}$

$\space$

$\sf\underline\bold\blue{Calculating\:the\:required\:values:}$

$\mapsto$ $\sf\bold{Radius=}$ $\sf\dfrac{20}{2}$

$\sf{Convert \: to \: the\:lowest\:term(Divide),}$

$\mapsto$ $\sf\underline\bold{Radius=10}$

☆Now we know the value of the radius . So now let's calculate the area of the circle.

$\space$

$\sf\bold{Area\:of\:circle:}$ π$\sf{ r \: ^{2} }$

$\sf\bold{Evaluating \: the\:required\:values:}$

$\sf\bold{Area\:of\:circle=3.1415(10)^2}$

$\space$

$\sf\bold{Area\:of\:the\:circle=3.1415\times10\times10}$

$\sf\bold{Now,}$

$\sf\bold{Area\:of\:the\:circle:3.1415\times100}$

$\space$

$\sf\underline\bold\green{Thus,Area\:of\:the\:circle\: is \: 314.15}$

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