The square with vertices (-a, -a), (a, -a), (-a, a), (a, a) is cut by the line y = x/3 into congruent quadrilaterals. The perimeter of one of these congruent quadrilaterals divided by a equals what? Express your answer in simplified radical form.
Call the length of the top side of one of the quadrilaterals, 2a
The length of the right side of this quadilateral (a - a/3) = (2/3)a = (2a)/3
The length of the bottom of the quadrilateral = sqrt [ ( a - - a)^2 + (a/3 - - a/3)^2 ] =
sqrt [ 4a^2 + (4/9)a^2 ] = a sqrt [ 36 + 4]/3 = (a/3)sqrt (40)
The left side of the quadrilateral = (a - - a/3) = (4a)/3
Perimeter of quadrilateral =
a [ 2 + 2/3 + sqrt (40)/3 + 4/3 ] = a [ 4 + sqrt (40)/3 ] = a [ 12 + 2sqrt (10) ] / 3
Dividing this by a = [ 12 + 2sqrt (10)] / 3 = 4 + (2/3)sqrt (10)