Practice:
https://www.ixl.com/math/geometry/similarity-ratios
https://www.thatquiz.org/tq-A/?-jg-l1i-m2kc0-na-p0
https://www.ixl.com/math/grade-8/dilations-graph-the-image
https://www.mathgames.com/skill/8.83-dilations-graph-the-image
Instruction:
https://www.youtube.com/watch?v=Yahk3U4sYlU
https://www.sophia.org/concepts/practice-with-dilations--2
https://www.mathsisfun.com/geometry/triangles-similar-finding.html