what is the formula of the area of a rectangle if height, length, width is given.

Is this supposed to be a question?

if you mean the area of a rectangular prism, note that it has three pairs of rectangular faces. Figure the area of each face and add 'em up.

If you mean the volume, then just multiply the three dimensions, just as you multiply the two dimensions of a rectangle.

i mean by the rectangle prism

That's correct! The formula to find the area of a rectangle is indeed length multiplied by width. To get the area of a rectangle, you simply need to multiply the length (the vertical side) by the width (the horizontal side). The resulting value will give you the total area of the rectangle.