How do i compute the area of the circle with diameter 6ft to the nearest tenth using 3.14 for pi

Answer 1

The most common way to write formula for the area of a circle, at least in the US, is:

A = πr², where A = area of the circle

r = radius of the circle

Here you are given the diameter of the circle. The diameter is the length of a line that goes through the center of the circle and touches both sides of the circle. You can think of it as the width of the circle. The radius is the length of a line that ends at the center of the circle, and ends at only one point on the circle. You can think of it as half the width of the circle. Because of this, the radius is half the diameter. Because our formula uses the radius, you will need to divide the diameter by 2 to be able to use the formula:

r = D / 2

= 6 / 2

= 3

Now, plug this number into our formula:

A = πr²

= (3.14)(3)²

= 28.26 remember your question asked for the nearest tenth, so we will need to round up

= 28.3 to the nearest tenth

In some fields, like engineering and physics, we almost are always given the diameter of a circle first. Instead of always dividing this number by 2 and then plugging it into the formula given above, we just rewrite the formula to be in terms of the diameter. Remember, the radius is half the diameter:

r = D / 2

Now take this and plug it into our formula above to get:

A = πr²

= π(D/2)²

= πD²/4

= 1/4πD²

If you used this formula, you could plug in the value given directly into the equation to get:

A = 1/4πD²

= 1/4π(6)²

= 28.26

= 28.3