In a unit circle, what is the length of an arc that subtends an angle of
π/4 radians?

A unit circle has radius 1, and thus circumference .

Since an angle of is one eighth of a whole turn, the length of an arc that subtends an angle of   radians will be one eighth of the whole circumference:

In fact, the radians have the property that, in the unit circle, the length of the arc is exactly the measure of the angle. In general, you have

where l is the length of the arc, r is the radius and is the angle in radians. So, if , you have

to find the unit price, we must figure out the cost of one item (in this case one dish towel).   to do this, we divide the total price ($7.92) by the number of items bought (for this problem it is 8, because there are eight dish towels in one pack).  

$7.92/8 = $0.99

therefore, the unit price, or the price of one dish towel, is $0.99.

hope this !