The starting point for much of the action on the field is home plate, which is a five-sided slab of whitened rubber, 17-inches square with two of the corners removed so that one edge is 17 inches long, two adjacent sides are 8½ inches, and the remaining two sides are 12 inches and set at an angle to make a point.
Home plate is 17 inches wide from corner to corner and covers an area of 216 square inches. Since the shape of home plate is pentagonal, the corners do not add any width to the plate.
3 complete rotations
17" width of home plate...
7 baseballs wide
17 inches wide
7 baseballs wide
No, the "black" is NOT part of home plate. Home plate is 17 inches wide. Some home-plate models have a black edge that extends beyond that 17 inches. The utility of that black edge is to protect the white edge of the actually plate from chipping.
home plate
If you're referring to home plate it is 17 inches wide and 17 inches from bottom to tip. The sides are 8 1/2 inches from the bottom to the angle leading to the tip and 12 inches along that angle.
There are three 90 degree angles. (Looking at home plate from a "pitcher's viewpoint), the wide "front" of home plate has 90 degree angles on both sides. The back point, e.g. "the heart of the plate," is also a 90 degree angle. The two angles closest to the batter's back foot are both 135 degrees. This is because these angles are the sum of a 90 degree angle and a 45 degree angle. The back "triangle" of home plate is a 45-45-90 triangle. Hope this helps.
I have found various answers all over. No official dimensions exist but plent of leagues play by it. Some manufacturers call it a "mat" or a "home plate extension" or a "carpet." One league even mandates a gap the size of a softball between the mat and the plate. I'm making my own and we won't be playing with a gap. So, the dimensions I have decided to use to make my own are 17" wide (same as home plate) and 26" long. The notch in it is 8.5" deep to match the shape of the plate. The new total rectangle dimentions including home plate thus will be 17" wide by 34.5" long (8.5" side edge length of the plate + 26" extension).
Any number. Depends on how wide the mid-oceanic ridge is.