how a can make this formula

Getting Started
1

Hi
i need to do surface area calculation
the formula is

surface area =2lw+2lh+2wh

how to calculate rectangular tank total surface area in mm

2

(length x width x 2) + (length x height x 2) + (width x height x 2)

or

((length x width ) + (length x height) + (width x height)) x 2

3

Dim surface_area as double = (2lw) + (2lh) + (2wh)

Just to be exact in Xojo syntax. In Xojo you need to explicitly mention the multiplication, So a * (star symbol = multiply symbol)

4

Ok

Thanks