Question

The diameter of a circle is 14 cm. The circumference is 43.9823 cm. Use the formula C =πd toapproximate the value of π to 8 decimal places.

Answer 1

3.14159285

Explanation:

This is simple one if you think about it for a minute: they give you the formula and two of the values, so solve for the 3rd one, which is
`\pi` in this case. (Just like solving for x in a typical equation.)

`C = \pi d`

`\pi = C/d` <-- key to this

Then you just plug in the values and divide:

`\pi = 43.9823cm/14cm`

Notice that the units of centimeters cancel out, which is good because
`\pi` is a unitless number.

So put in your calculator: 43.9823 ÷ 14 and get:

3.14159285

And by the way, them asking for 8 decimal places isn't supported by the numbers you input. "14 cm" might be exactly 14cm to 6 places, but the cirucumference number is only precise to 6 significant digits, so that limits the calculated power of pi to only 5 decimal places (5 plus the place where 3 is, so 6 significant digits).

You could argue that with your teacher for brownie points.

Be good.