Area of a trapezoid. Area of a triangle given sides and angle. Area of a circle p d2 2.
Here the Greek letter p represents the constant ratio of the circumference of any circle to its diameter approximately equal to 314159.
Area of a triangle given base and height. It is equal to half the diameter. If you know the circumference of a circle you can use a revision of the formula for the area of a circle. It can be determined easily using a formula A pr2 Pi r-squared where r is the radius of the circle.