In any square pyramid, which of the following squared quantities are in arithmetic progression?

1. From half-base-edge a/2, height h and slant height l: l² = h² + (a/2)². 2. From slant height l, half-base edge a/2 and lateral edge e: e² = l² + (a/2)². 3. Adding both gives l² + e² = h² + 2(a/2)² + l², so e² - l² = (a/2)² and l² - h² = (a/2)². 4. The differences e² - l² and l² - h² are equal — i.e. h², l², e² form an arithmetic progression. 5. So the squares of height, slant height and lateral edge are in arithmetic sequence. _Source: SCERT Kerala Std X Mathematics Part-2, Chapter 7-8 (pp 180-199, 2019 ed.)._