1, the perimeter of the rectangle = (length+width) ×2 C=(a+b)×2.

2. The circumference of a square = side length ×4 C=4a.

3. Area of rectangle = length× width S=ab

4. Square area = side length x side length s = a.a = a.

5. Area of triangle = base × height ÷2 S=ah÷2.

6. parallelogram area = bottom x height S=ah

7. trapezoidal area = (upper bottom+lower bottom) × height ÷ 2s = (a+b) h ÷ 2.

8. Diameter = Radius× 2D = 2r Radius = Diameter ÷2 r= d÷2

9. The circumference of a circle = π× diameter = π× radius× 2c = π d = 2π r.

10, circular area = pi × radius× radius? =πr

1 1, the surface area of a cuboid = (length× width+length× height+width× height) × 2.

12, cuboid volume = length× width× height V =abh.

13, the surface area of the cube = side length × side length× ×6 S =6a.

14, volume of cube = side length x side length x side length v = a.a.a = a.

15, lateral area of cylinder = circumference of bottom circle × height S=ch.

16, surface area of cylinder = upper and lower bottom area+side area.

s = 2πr+2πRH = 2π(d÷2)+2π(d÷2)h = 2π(c÷2÷π)+Ch

17, cylinder volume = bottom area × height V=Sh

V=πr h=π(d÷2) h=π(C÷2÷π) h

18, volume of cone = bottom area × height ÷3.

v = sh÷3 =πr h÷3 =π(d÷2)h÷3 =π(c÷2÷π)h÷3