The blue squares in the corners and at the point are 90° angles.

 

easy peasy.
think of this in 2 shapes a rectangle sitting on top of a triangle
you have a triangle with a base of 17 and to legs of 12
now if you split that triangle down the middle you have two right angle triangles.
each right angle triangle has a base of 8.5 and a hypotenuse of 12.
Pythagorean theorem tells us that the third leg will be 8.4705371730487081311459128353654, which is nearly 8.5.
you have your self rougly a 45 degree angle.

a little but of trig tells us that it is actually 44.9005279606889

and then come to think of it you could make it a 45 by turning your 12 legs into 12.0208152801713

 

Don't use math, you'll really screw it up because home plate dimensions as spelled out by the rule book are mathematically impossible. Plus you don't need math. This is one of the few times where I think something from a rule book as big as the MLB rule book is easy to comprehend:

It shall be a 17-inch 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.

Just use those numbers like Rippers diagram and make a template.

 

Thanks. I was actually going to make it a little bigger than this. I'll get back to you this evening with actual dimensions.

 

All you need to remember is that the sum of a polygon's angles is 540°. So, if you know that home plate has the three 90° angles and the other angles are equal you can calculate that the other angles must be 135° each.

Like so:

90° + 90° + 90° = 270°

540° - 270° = 270°

270° ÷ 2 = 135°

 

Ok. Thank you

 

Don t use math, you ll really screw it up because home plate dimensions as spelled out by the rule book are mathematically impossible. Plus you don t need math. This is one of the few times where I think something from a rule book as big as the MLB rule book is easy to comprehend:

It shall be a 17-inch 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.

Just use those numbers like Rippers diagram and make a template.

- ColonelTravis

 

Outstanding.

 

Here is how I did mine: