what is the diameter of a major league baseball
Baseball (ball) Throughout the 20th Century, Major League Baseball used two technically identical but differently marked balls. The American League had "Official American League" and the American League's president's signature in blue ink, while National League baseballs had "Official National League" and the National League president's signature in black ink. According to Bob Feller, in the 1930s, when he was a rookie in the National League, baseball laces were black, intertwined with red; the American League's were blue and red.[9] In 2000, Major League Baseball reorganized its structure to eliminate the position of league presidents, and switched to one ball specification for both leagues. Under the current rules, a major league baseball weighs between 5 and 5 1⁄4 ounces (142 and 149 g), and is 9 to 9 1⁄4 inches (229–235 mm) in circumference (2 7⁄8–3 in or 73–76 mm in diameter).[10] There are 108 double stitches on a baseball, or 216 individual stitches.
Baseball field In roughly the middle of the square, equidistant between first and third base, and a few feet closer to home plate than to second base, is a low artificial hill called the pitcher's mound. This is where the pitcher stands when throwing the pitch. Atop the mound is a white rubber slab, called the pitcher's plate or pitcher's rubber. It measures 6 inches (15 cm) front-to-back and 2 feet (61 cm) across, the front of which is exactly 60 feet 6 inches (18.44 m) from the rear point of home plate. This peculiar distance was set by the rule makers in 1893, not due to a clerical or surveying error as popular myth has it, but intentionally (further details in History section).