The pythagorean theorem will help with this! First take triangle ACD, AD^2 + CD^2 = AC^2. Plug in, AD^2 + 16 = 25. AD^2 = 9. AD = 3. I'm not exactly sure how to find DB, but I can assume it's double of AD< so 6. We know CD is 4, so 4^2 + 6^2 = CB^2. 16 + 36 = CB^2. CB = sqrt62
Sorry if this isn't exactly right, there's no exact way to find DB.
