what is the area of a right-angled triangle
Right triangle If the incircle is tangent to the hypotenuse AB at point P, then denoting the semi-perimeter (a + b + c) / 2 as s, we have PA = s − a and PB = s − b, and the area is given by
Perpendicular The legs of a right triangle are perpendicular to each other.
Circle As proved by Archimedes, in his Measurement of a Circle, the area enclosed by a circle is equal to that of a triangle whose base has the length of the circle's circumference and whose height equals the circle's radius,[7] which comes to Ï€ multiplied by the radius squared:
Standard deviation Let X be a random variable with mean value Î¼: