When engineers build bridges, they use some important math ideas, especially about angles. Let's break it down:

1. Understanding Angles: Engineers need to figure out the right angles to make sure the bridge is safe and strong. For instance, when measuring how high a bridge is above water, they look at the angle from a boat below.

2. Using Sine, Cosine, and Tangent: They use special math functions called sine, cosine, and tangent to find out lengths and heights.

   For example, if an engineer knows the distance from the base of a bridge to the top of a support tower, and they also know the angle they measured, they can find the height using the tangent function.

   Here’s a simple formula:

   $\text{Height} = d \times \tan(\theta)$

   In this formula, ( d ) is the distance, and ( \theta ) is the angle.

3. Load Distribution: Trigonometry helps engineers understand how weight is spread across different parts of the bridge.

All in all, these math ideas help engineers design bridges that are safe, strong, and can handle all kinds of pressure and weight in the real world.