If the polygon is regular 1/2*apothem*number of sides*side length, or you can divide the polygon into triangles and quadrilaterals and add the areas of those together.

Andante is the tempo of a piece of music in which there are in between 84 and 100 beats per minute. You can hear the various speeds of andante on a metronome, such as this one: www.metronomeonline.com