A rectangular prism is a solid shape with six rectangle faces and three dimensions. Some people also call them an oblique, a cuboid, or a rectangular hexahedron. A right rectangular prism is also an acceptable term. The shape can have sides that lean to one side as well.
To work out the volume of a rectangular prism, you need to use the formula below.
In the formula, you will see three letters = h, w, and l.
H = height
W = width
L = length
The formula is h x w x l
Let’s say you want to find the volume of an apple carton. Follow these steps with example measurements below.
1. Identify the length of the box - 20 inches long
2. Identify its width – 18 inches wide
3. Measure its height – 13 inches high
4. Calculate the cuboid volume
Volume = 13 x 18 x 20 = 4,680 in³
Identifying the area of a rectangular prism involves a long-winded sum, but it’s as effortless as determining the volume – especially with a rectangular prism calculator. As you know, the prism has six faces which include three parallel rectangle pairs. Add all the faces together to get the surface area.
The formula is as follows:
Surface area = 2 x (h x w) + 2 x (h x l) + 2 x (l x w) = 2 x (h x w + h x l + I x w)
Using the same dimensions of the apple carton above, we’ll work through it step by step.
1. Calculate the surface areas
Height x width = 13 x 18 = 234 in²
Height x length = 13 x 20 = 260 in²
Length x width = 20 x 18 = 360 in²
2. Add all figures together then divide by two
260 + 360 + 234 / 2 = 427 in²
The apple carton’s surface area is 427 in².
Alternatively, you can use a rectangular prism calculator instead of having to work the value out by hand.
If you want to know the diagonal value of a rectangular prism, then you will see it’s a fairly straightforward process.
Use this formula:
Diagonal = √ (l² + h² + b²)
The formula is very similar to that in use with the Pythagorean theorem.
Did you know the rectangular prism is not the only shape for which you can use a calculator to get the volume? There are several others. If you ever need to find the volume of a cone, pyramid, sphere, or any other three-dimensional shape, there is sure to be a calculator to help.