The radius is from center to point on a circle.
So your task is count distance between two points: S(10,6) and A(-3,3).
Distance between two points A(x1, y1) and B(x2, y2) count from this formula:
The box has volume
11 in × 3 in × <em>x</em> in = 33<em>x</em> in³
and surface area
2 (11 in × 3 in + 11 in × <em>x</em> in + 3 in × <em>x</em> in) = (66 + 28<em>x</em>) in²
The volume and area have the same value if
33<em>x</em> = 66 + 28<em>x</em>
Solve this equation for <em>x</em> :
33<em>x</em> - 28<em>x</em> = 66
5<em>x</em> = 66
<em>x</em> = 66/5 = 13.2
It will take 120 feet for the 36mph car to stop
4/5 is the the fraction of a pound is eighty pence
4.75 Kilometers, you just divide by 1000