Answer:
15 feet
Explanation:
A typical diagram has been shown.
Joel's hand touches the bottom of the pool, point A as shown, 12 feet below the surface of the water.
Todd's foot is at the diving platform, at point B as shown, 3 feet above the surface of the water.
Let S be the point on the surface of the water.
So, the vertical distance between Joel's hand and todd's feet
=AS+SB
=12+3
=15 feet.