Question 293198
It will trace out a square who's sides
are 1 radius away from the outside square
The outside square's sides are {{{10}}} units
apart. The inside square's sides are {{{2r}}}
smaller, so {{{10 - 2r = 10 - 4}}}
{{{10 - 4 = 6}}}
The perimeter of a square with sides = 6 is
{{{4*6 = 24}}} units
The answer is (b)