Solve similar triangles (basic)

Given two similar triangles and some of their side lengths, find a missing side length.

Problem

Triangle A, B, C is similar to triangle D, E, F.
Solve for r.
r, equals
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3, slash, 5
  • a simplified improper fraction, like 7, slash, 4
  • a mixed number, like 1, space, 3, slash, 4
  • an exact decimal, like 0, point, 75
  • a multiple of pi, like 12, space, p, i or 2, slash, 3, space, p, i