Circumference is a linear distance. So if the diameter is in feet, then the circumference is also in feet (not square feet or cubic feet)
-------------------------------------
Example:
Let's say we had a circle with diameter d = 10 feet
The circumference is approximately...
C = pi*d
C = 3.14*10
C = 31.4
The circumference is roughly 31.4 feet
The circumference is essentially the distance around the circle's edge. We can use a flexible ruler or a string to help measure out this distance, or you can imagine laying the circle's edge to be placed along a straight line, which is another way to help measure the perimeter.
Hopefully this is right :)
I know similar questions and have answers. do you want
5.8 × 10⁻¹ = 0.58
7.4 × 10⁰ = 7.4
0.58 - 7.4 = -6.82
so
(5.8 × 10⁻¹) - (7.4 × 10⁰) = -6.82 × 10⁰
4/5 = you divide it so you get 0.8 which is 80%