Equilateral triangle terms of side length "a" can be derived directly using the Pythagorean theorem or using trigonometry. The area of a triangle is half of one side "a" times the height "h" from that side: The legs of either right triangle formed by an altitude of the equilateral triangle are half of the base "a", and the hypotenuse is the side "a" of the equilateral triangle. The height of an equilateral triangle can be found using the Pythagorean theorem so that Substituting "h" into the area formula (1/2)"ah" gives the area formula for the equilateral triangle: Using trigonometry, the area of
Jack (given name) of the word is linked to the name being used as a by-name for a man. Jack (given name) Jack is a male given name. In recent decades, Jack has become one of the most common names for boys in many English-speaking countries. While Jack is now a proper name in its own right, in English; it was traditionally used as a diminutive form of John. It can also be used as a diminutive for: Jacob, Jason, Jonathan, Johann, Johannes, Joachim and sometimes for James, from its French form Jacques. It is also used as a female given name (often