Two poles of heights 15 m and 6 m stand 12 m apart. The distance between their tops is

1. Horizontal distance = 12 m; height difference = 9 m. 2. Form a right triangle: d^2 = 12^2 + 9^2 = 144 + 81 = 225. 3. d = 15 m. 4. So the tops are 15 m apart. _Source: Selina Concise Mathematics Class 9, Ch on Pythagoras Theorem (Mistral OCR'd PDF), section on application_