To be a Civil Engineer you need to know many math qualities. You need to know:
The Real Number System- You have to measure the lengths of beams for bridges as shown in the picture below
Geometric Properties- You need to know geometric properties to decide on shapes of bridges as well as the correct angle measurements of them
Pythagorean theorem- You need to know how to use the Pythagorean theorem to find the measurements of the hypotenuse on a triangle. On many bridges there are lots of triangles.
Math is used in many jobs and civil engineering is one of them
Skip to 1:35 in the video