1. **State the problem:** We have a truck on a ramp that forms a right triangle. The ramp length (hypotenuse) is 75 feet, and the vertical height is $x$. We want to find the tipping angle $\theta$ of the ramp. 2. **Formula used:** The tipping angle $\theta$ is the angle between the horizontal ground and the ramp. Using trigonometry, specifically the sine function: $$\sin(\theta) = \frac{\text{opposite}}{\text{hypotenuse}} = \frac{x}{75}$$ 3. **Solve for $\theta$:** $$\theta = \arcsin\left(\frac{x}{75}\right)$$ 4. **Explanation:** The sine of the tipping angle is the ratio of the vertical height $x$ to the ramp length 75 feet. To find the angle, we take the inverse sine (arcsin) of this ratio. 5. **Important note:** The value of $x$ must be less than or equal to 75 for the angle to be valid (since sine values range from -1 to 1). **Final answer:** $$\boxed{\theta = \arcsin\left(\frac{x}{75}\right)}$$