# How Are Triangles Used in the Real World?

**Triangles are used to make rafters in buildings and curved domes.** Some bridges have triangular structures, and the Egyptians made triangular-shaped pyramids. The shapes help surveyors use triangulation to determine the distance of a specific point from two other points of a known distance apart. Triangulation may be used to measure distances around corners and when digging tunnels, and carpenters use a right-angled triangle to take measurements.

Right-angled triangles are used alongside trigonometry to solve real-world distance problems, such as the distance a ladder of a known length can go up against a wall, if the angle the ladder makes with the ground is also known. The concept also helps determine the flight path (the distance traveled from the original point and bearing) of a plane that flies at a known speed for some hours, turns at a known angle at the same speed and continues to fly for a known number of hours.

A sandwich may be shaped like a triangle. A staircase makes a right-angled triangle, with its length being the hypotenuse. Also, a right-angled triangle forms when one stands at the top of tower, observes an oncoming ship and attempts to calculate the distance between the ship and the bottom of the tower or the angle of elevation from the top.