You haven't given enough information. What kind of polygon is it?
The area of a four-sided polygon is base times height.
triangle
A triangle.
The surface area of a pyramid is the area of all the faces of the pyramid, for a pyramid with apex in the centre and a regular polygon as its base, (the bottom of a pyramid is the base, it is regular if all sides are the same length) the surface area is: B + 1/2(P * H) where B is the area of the base, P is the perimeter (area around) the base and H is the height of the pyramid.
It's different for every polygon. For example, for a triangle, it's (1/2) x (base) x (height). For a rectangle, it's (the entire) (base) x (height).
Base: Depending on the shape of the base, use the formula for a square, a regular polygon, etc. Height: This must be measured (or calculated) perpendicular to the base.
A regular pyramid has an equilateral triangle base, not just a regular polygon. It has an apex above the centre of the base.
Base times Height divided by three. The base is perpendicular to the height, which ends at the highest point of the pyramid. To find the area of the base, one simply uses 2-dimensional geometry. Triangle: Base of triangle times height of triangle over 2 Any regular polygon: Apothem (perpendicular distance from orthocenter to a side) times perimeter divided by 2.
A regular pyramid has a regular polygon base and a vertex over the center of the base. By:Cherrylvr :)
Naturally its perimeter and area will increase accordingly
You didn't say it was a regular pentagon. For an arbitrary pentagon, you would calculate its area as you would for any polygon: divide it up into triangles, and add up the areas of the triangle. The area of a triangle is 1/2 times the base times the height, the height being the length of the perpendicular dropped to the base from the opposite vertex.
regular pyramid