A ladder 5 m long is leaning against a wall. The bottom of the ladder is pulled along the ground, away from the wall, at the rate of 2 cm/s. How fast is its height on the wall decreasing when the foot of the ladder is 4 m away from the wall?

Explanation

To solve the problem step by step, we will use the Pythagorean theorem and related rates.

### Step 1: Understand the Problem
We have a ladder that is 5 meters long leaning against a wall. The bottom of the ladder is being pulled away from the wall at a rate of 2 cm/s (which is 0.02 m/s). We need to find out how fast the height of the ladder on the wall is decreasing when the foot of the ladder is 4 meters away from the wall.

### Step 2: Set Up the Variables
Let:
- \( x \) = the distance from the wall to the foot of the ladder (in meters)
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