Still need more practice? You can go to these links for additional practice:
https://www.khanacademy.org/math/geometry/hs-geo-transformations/hs-geo-dilations/e/performing-dilations
https://www.khanacademy.org/math/geometry/hs-geo-transformations/hs-geo-dilations/e/defining-dilations-2
https://www.khanacademy.org/math/geometry/hs-geo-transformations/hs-geo-dilations/e/dilations
You may also find these video links helpful:
https://www.khanacademy.org/math/geometry/hs-geo-transformations/hs-geo-dilations/v/dilating-points-example
https://www.khanacademy.org/math/geometry/hs-geo-transformations/hs-geo-dilations/v/dilation-scale-factor
https://www.khanacademy.org/math/geometry/hs-geo-transformations/hs-geo-dilations/v/thinking-about-dilations
https://www.khanacademy.org/math/geometry/hs-geo-transformations/hs-geo-dilations/v/dilating-shapes-shrinking