If the steel rod has a circular cross-section - the usual case - you can use the formula for a cylinder. Since the area of the base is quite small, it can be ignored - just calculate length x diameter x pi.
The smallest commercially (easily) available steel rod is about 0.014" diameter.
length x width = area
Calculate the area of the room. Calculate the area of the window (or whatever opening) Room Area*100/Window Area
It is not possible to calculate the area given only the volume.
Average area
Calculate the area to be covered. (A) Calculate the area per board or pack (B) Divide (B) into (A)
to calculate the area of the front surface of a box you should
To calculate Cross Sectional Area: Width x Depth
You need to:* Calculate the surface area * Calculate the volume * Divide the surface area by the volume
To calculate plinth area of a house, you would calculate the thickness of walls that external along with the entire carpet.
The 45 degrees is an angle. To calculate an area the length and width are needed.
How to calculate the net floor area when you know the gross floor area