Since we are looking for the change, we must take the

(Ending Point – Starting Point)/Starting Point * 100%

(22752 – 12979)/12979 * 100%

9773/12979 * 100%

0.753 * 100%

75%

This is a percentage increase problem. 

Easiest approach :  2500 x 1.12 = 2800

In this way you are adding 12% to the original.

Using the formula, find 12% of 2500

12/100 = x/2500, 

30000 = 100x

300 = x

Now add that to the original to find the new production:

2500 + 300 = 2800

If we plug-in a radius of 5, then a 20% increase would give us a new radius of 6 (which is 1.2 x 5).  The area of the new circle is π(6)2 = 36π, and the area of the original circle was π(5)2 = 25π .  The numerical increase (or difference) is 36π - 25π = 11π.  Next we have to divide this difference by the original area: 11π/25π = .44, which multiplied by 100 gives us a percent increase of 44%.  The percent increase = (the numerical increase between the new and original values)/(original value) x 100. The algebraic solution gives us the same answer.  If radius r of a certain circle is increased by 20%, then the new radius would be (1.2)r.  The area of the new circle would be 1.44 π r2 and the area of the original circle πr2.  The difference between the areas is .44 π r2, which divided by the original area, π r2, would give us a percent increase of .44 x 100 = 44%.

$1,800,800 divided by 100 equals 18,008 and $2,130,346 divided by 18,008 is 118.3

So we know that $2,130,346 is 118.3% of the sales in the previous year. Hence sales increased by 18.3%.

Pick any number to be the original diameter. 10 is easy to work with. If the diameter is 10, the radius is 5. The area of the original image is A = πr², so the original area = 25π. Now we increase the diameter by 75%, so the new diameter is 17.5. The radius is then 8.75. The area of the enlarged image is approximately 77π. To find the percentage by which the area has increased, take the difference in areas divided by the original area.  (77π - 25π)/25π = 51π/25π = 51/25 = 2.04 or approximately 200%

The area of a square is given by , and if the side is doubled, the new area becomes .  The increase is a factor of 4, which is 400%.

We will use the formula  to solve this one

compute the terms in the parentheses:

If we rewrite the term in parentheses to match the form of the original formula, we can find the rate without having to do extra computation.

 So, the rate is a decrease by 0.784%, which we round to 0.8%

If we use r to denote the original radius of the circle, then according to the formula:

the new radius R, is given by

Therefore, the new area is:

Or

Since (pi)r² is the area of the original circle, the rate of the increase is 21%