Final answer:
The watermelon must fly approximately 27.7 units for the man to catch it without moving.
Step-by-step explanation:
To determine how far the watermelon must fly in order for the man to catch it without moving, we can use the distance formula. The distance between the launch point (21,8) and the catching point (26,20) can be calculated using the formula:
Distance = sqrt((x2 - x1)^2 + (y2 - y1)^2)
Substituting the values, we get:
Distance = sqrt((26 - 21)^2 + (20 - 8)^2) = sqrt(25^2 + 12^2) = sqrt(625 + 144) = sqrt(769) ≈ 27.7 units
Therefore, the watermelon must fly approximately 27.7 units for the man to catch it without moving.