**explain how inverse trigonometric functions are used in road design**

**Answer:**

Curves that connect two straight sections of a road are often constructed as arcs of circles. there is a central angle of a circular arc which has a radius. Each radius line is perpendicular to one of the straight sections. The straight sections are therefore tangent to the arc. That’s how it is divided in to two right angle triangle. Inverse trigonometric functions are used to calculate angles and arc lengths of such curves.