Salvador and Armando use a land surveying tool, a clinometer, to determine the angle of depression from their position on a bridge to a person in a boat on the water. They know the bridge is 110 feet above the water and the angle of depression is 40 degrees.

To find the horizontal distance from Salvador and Armando to the boat, we can use the relationship defined by a right triangle. In this case, the height of the bridge is the opposite side to the angle of depression, and the horizontal distance to the boat is the adjacent side.

Using the tangent function, we can represent this relationship mathematically:

\[ \tan(\theta) = \frac{\text{opposite}}{\text{adjacent}} \]

Where:

• \(\theta\) is the angle of depression (40 degrees)
• The opposite side is the height of the bridge (110 feet)
• The adjacent side is the horizontal distance (let's call it \(d\))

Rearranging the formula to solve for \(d\) gives us:

\[ d = \frac{\text{opposite}}{\tan(\theta)} \]

Now we can plug in the values:

\[ d = \frac{110 \text{ feet}}{\tan(40^\circ)} \]

Calculating \(\tan(40^\circ)\):

\(\tan(40^\circ) \approx 0.8391\)

Now substituting this value back into the equation for \(d\):

\[ d \approx \frac{110}{0.8391} \approx 131.0 \text{ feet} \]

So the horizontal distance from Salvador and Armando to the boat is approximately 131 feet. Therefore, the answer is:

131 feet.