figuring out the acreage of a circle

Sorry to be an idiot – I did the math, but I don’t trust myself, and I can’t find an online converter to check it against.

I need the acreage equivalent of a circle that’s five miles in diameter. Area is Pi r[super]2[/super], so pi x5[super]2[/super], or pi x 25, or roughly 78.5 square miles, which would be a tad over 50K acres.

Is that right?

ETA: and how the hell do you do superscripts?

Well your first problem is that r isn’t 5; it’s 2.5.

So 2.5 squared is 6.25. Times pi is about 19.6 square miles.

ETA: And 19.6 sq miles = about 12.5k acres.

On preview: what he said.

As for superscripts, no idea.

I’m no geometry whiz, but the radius is half the diameter. So 3.1415 X 2.5 sq (6.25) = 19.63.

StG

:smack:

This is why I wanted someone to check what I was doing! (My standard disclaimer is that I’m number dyslexic. No. Seriously.)

ya what they said

No, wait, sorry. The RADIUS of the circle is 5 miles, not the diameter.

God, could we just pretend I never started this?

N[sup]o[/sup].

Sup, super, whatever. :stuck_out_tongue:

Well, we can’t figure it out unless you also give us the ulna. Duh!

If the radius of the circle was five miles, your first calculation was OK. (I kept an additional decimal, so I got 78.54.)

Your self-check for that is also pretty easy. A radius of 5 is a diameter of 10, of course. A circle with a diameter of 10 would fit into a square of 10 units to each side with a tangent on the mid-point of every 10 unit side line segment. A square that is 10 x 10 would be 100 square units, so a circle of 78.54 units for a square with the corners knocked off seems realistic.

Google calculator is your friend.

Your square mile calculation is correct. 78.5398 square miles.

Hit Google calculator and feed it ‘78.5398 square miles in acres’

and get 78.5398 (square miles) = 50 265.472 acres for your result.

2[sup]99[/sup] = 2[sup]99[/sup]

Now that the question is answered, may I point out that radius is the only word for radius?

Semidiameter. :stuck_out_tongue:

Are you mocking me, sir? Given how confused I got just asking the question, I am forced to assume you are. :frowning:

Just in case you’d like to offer the answer in metric units, that would equate to 20341.7297 hectares.

I’m guessing that word was specifically made up for this purpose - like those new words that rhyme with orange.

Heh. Actually, it’s an actual word, with a slightly different meaning; apparently corrupted by my previous source.