What is 15 sides shape?

A 15-sided polygon is called a pentadecagon. It is a geometrical figure that has 15 sides and 15 angles. All 15 angles of a pentadecagon are equal to 156 degrees, and the interior angles of a regular pentadecagon are 168 degrees. A regular pentadecagon can be drawn using a compass and straightedge, and it is a symmetrical shape. The area of a regular pentadecagon can be calculated using trigonometric functions, since it can be divided into 15 congruent triangles. The formula for finding the area of a regular pentadecagon is A = (15/4) × a2 × cot(π/15), where a is the length of one of its sides. Pentadecagons occur in nature in various plant structures, such as the seed head of a sunflower.