Perimeter formula

Square

      4 × side = 4a

Rectangle

2 × (length + width) = 2(l + b)

Parallelogram

2 × (side1 + side2) = 2(a + b)

Triangle

Sum of side = a+b+c

Regular n-polygon

n × side

Trapezoid/Trapezium

Sum of side =  a+b+c+d

Circle

2 × pi × radius = 2πr

pi (π) = 3.1415926535 ...

Area formula

Square

side² = a²

Rectangle

length × width =lb

Parallelogram

base × height = bh

Triangle

Trapezoid/Trapezium

Circle

pi × radius² = πr²

Cube (surface)

6 × side² = 6 × a²

Sphere (surface)

4 × pi × radius² = 4πr²

Cylinder (surface of side)

बेलन का वक्र पृष्ट क्षेत्रफल

perimeter of circle × height = 2πrh

Cylinder (whole surface)

बेलन का सम्पूर्ण पृष्ट क्षेत्रफल

Areas of top and bottom circles + Area of the side

= 2(pi × radius²) + 2 × pi × radius × height

= 2πr² + 2πrh

Cone (surface)

pi × radius × side

Torus (surface)

pi² × (radius2² - radius1²)

Ellipse

pi × radius1 × radius2 = π×r₁×r₂