So you have the following equation:
A = 2πpw
When there are no space inbetween letters, that means they are being multiplied, so we can rewrite the equation like:
a = 2π × p × w
You know what A is, and what w is, so first substitute in the values:
A = 2π × p × w (substitute in values for A and w)
22 = 2π × p × 2 (we want to get p by itself, so first divide both sides by 2, to get rid of the 2 that is next to the p)
11 = 2π × p (divide both sides by 2π, to get p all by itself)
11 ÷ 2π = p
Now just type in [11 ÷ 2π] into a calculator to get what p is:
p = 11 ÷ 2π
p = 1.75 cm (rounded to 2 decimal places)
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Answer:
p = 1.75