Why is home plate a pentagon rather than a square?

Answer 1

Home plate began its Baseball career in the nineteenth century as a twelve-inch square, set down like a diamond, with the two sides forming the beginning of the foul lines. Home is the compass by which a baseball field is set. Those foul lines extend up the foul poles and on into infinity. It's the diamond of home plate that starts them running. In the winter of 1899 the Rules Committee extended the bottom of the plate (that is, the side facing the pitcher), creating the foundation of the home plate pentagon/house. That year's Spalding Guide tells us the committee felt the pitcher was handicapped by having to "cut the corners" of the old twelve-inch square. The umpire also found it difficult to judge which pitched balls caught those corners. The guide adds that by making the front of the plate square with a width of seventeen inches, the pitcher is able to see the width of the plate better and the umpire can judge balls and strikes with less difficulty. Moreover, the front of the plate was squared off towards the pitcher to help prevent injury to the batter. Before the change, if the ball hit the edge of the plate, it would skip off at an acute angle. With a perpendicular edge facing the trajectory of the pitch, any ball hitting the edge would be deflected upward instead of skew. the two foul lines form the back edge of the plate

Answer 2

Yes, even though home plate is not shaped like an equal-sided pentagon, it is still a pentagon because it has five sides, just like a square is a rectangle.