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Computer Science : Formula for geometrical figures

pi (π)=3.1415926535 ...

Perimeter formula

Square4 × side
Rectangle2 × (length + width)
Parallelogram2 × (side1 + side2)
Triangleside1 + side2 + side3
Regular n-polygonn × side
Trapezoidheight × (base1 + base2) / 2
Trapezoidbase1 + base2 + height × [csc(theta1) + csc(theta2)]
Circle2 × pi × radius
Ellipse4 × radius1 × E(k,pi/2)
E(k,pi/2) is the Complete Elliptic Integral of the Second Kind
k = (1/radius1) × sqrt(radius12 - radius22)

Area formula

Squareside2
Rectanglelength × width
Parallelogrambase × height
Trianglebase × height / 2
Regular n-polygon(1/4) × n × side2 × cot(pi/n)
Trapezoidheight × (base1 + base2) / 2
Circlepi × radius2
Ellipsepi × radius1 × radius2
Cube (surface)6 × side2
Sphere (surface)4 × pi × radius2
Cylinder (surface of side)perimeter of circle × height
2 × pi × radius × height
Cylinder (whole surface)Areas of top and bottom circles + Area of the side
2(pi × radius2) + 2 × pi × radius × height
Cone (surface)pi × radius × side
Torus (surface)pi2 × (radius22 - radius12)

Volume formula

Cubeside3
Rectangular Prismside1 × side2 × side3
Sphere(4/3) × pi × radius3
Ellipsoid(4/3) × pi × radius1 × radius2 × radius3
Cylinderpi × radius2 × height
Cone(1/3) × pi × radius2 × height
Pyramid(1/3) × (base area) × height
Torus(1/4) × pi2 × (r1 + r2) × (r1 - r2)2

Source: Spiegel, Murray R. Mathematical Handbook of Formulas and Tables.
Schaum's Outline series in Mathematics. McGraw-Hill Book Co., 1968.