A swimmer can swim in still water at a rate 4.0 km/h. If he swims in a river flowing at 3.0 km/h and keeps his direction (with respect to water) perpendicular to the current, find his velocity with respect to the ground.

Explanation

To solve the problem of finding the swimmer's velocity with respect to the ground, we can break it down into a few clear steps.

### Step-by-Step Solution:

1. **Identify the velocities**:
- The swimmer's speed in still water (V_swimmer) = 4.0 km/h.
- The river's speed (V_river) = 3.0 km/h.
- The swimmer swims perpendicular to the river's current.
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