Why is the home plate shaped differently than other bases? The home base went through major shape changes over the years. The irregular pentagon shape of the home base that we know and love today was developed by Robert Keating and introduced as a viable option for the 1900/1901 baseball season. The rear corners, which extend to a point, are made to be perpendicular to the first and third base lines. The biggest advantage of the new shape was that it made the edges of the strike zone more visible to pitchers and umpires and, therefore, improved the consistency of calling strikes.

Source: MLB.com