An estimation is made by slightly rounding the numbers, then multiplying , adding, subtracting, or dividing.
In this case , to make an estimate, I would round 114 to 100, and 92 to 90... 100 x 90 = 9,000 sq in
You can of course round closer than that, depending on how accurate you want it to be, but the exact answer is 10,488, Wich you can round to 10,000 or 10,500
Hope this helped :)
