What triangle starts with p?

The triangle that starts with the letter "P" is the "Pythagorean triangle." This type of triangle follows the Pythagorean theorem, where the squares of the lengths of the two shorter sides (legs) sum up to the square of the length of the longest side (hypotenuse). An example of a Pythagorean triangle is the 3-4-5 triangle, where (3^2 + 4^2 = 5^2).