Content

• To step
• Method 1 of 2: Method 1: Area = 2ab + 2bc + 2ac
• Method 2 of 2: Method 2: Surface = 2B + Ph
• Tips

A rectangular prism is a difficult name for a 6-sided object that is very recognizable to everyone - the box. Think of a regular brick or a shoe box, and you know exactly what a rectangular prism is. This article will show you how to calculate the area of ​​this shape.

To step

Method 1 of 2: Method 1: Area = 2ab + 2bc + 2ac

1. Understand what a rectangular prism is. When you look at the example below, you will see that there are 6 sides in total. Each side is exactly the same as the side opposite, so there are really only 3 rectangles to deal with. If you just find the area of ​​each of the 3 rectangles, add them together and multiply by 2, you have the total area. Let's take it step by step.
   • The box in our example has a width of 4 (a), a length of 5 (b), and a height of 3 (c).
2. Learn the formula. To calculate the area of ​​a rectangular prism, use the following formula: 2ab + 2bc + 2ac
   • What does that mean? To put it in plain English, it means that you multiply the width by the length, and multiply that by 2. Then you multiply the length by the height, and you multiply that result by 2. Then you measure the width multiplied by the height, and multiply that by 2. Finally, add the three results together to get your final answer. Let's do that step by step.
3. Find the surface of the base side. The base side is the bottom of the shape, here yellow. To find its area, multiply the length by the width. The first part of the formula is 2ab, so 2ab = 2 * (4 * 5) = 2 * (20) = 40
4. Find the area of ​​the long side. This one is purple here. You can find this by multiplying the length by the height. The middle part of the formula is 2bc, so 2bc = 2 (5 * 3) = 2 * (15) = 30.
5. Finally, you will find the surface of the short side. This one is green here. The last part of the formula is 2ac, so 2ac = 2 (4 * 3) = 2 * (12) = 24.
6. Add them up now. 2ab + 2bc + 2ac = 40 + 30 + 24 = 94. The area of ​​this rectangular prism is 94 square units.

Method 2 of 2: Method 2: Surface = 2B + Ph

1. Learn the formula. To calculate the area using the perimeter of the base, we use the formula 2B + Ph. This is what the letters mean:
   • B = Area of ​​the base.
   • P = Perimeter (or perimeter) of the base.
   • H = Height of the prism.
2. Use the same rectangular prism as in Method 1 above.
3. Calculate the area of ​​the base (B). The area of ​​the base is 2ab = 2 (4 * 5) = 20.
4. Calculate the circumference. The circumference of the base side is found by adding the length of each side. If we look at it as a formula, it is 2a + 2b. In our example, we know that the base has a width of 4 and a length of 5. Our circumference is 2 (4) + 2 (5) = 8 + 10 = 18.
5. Put the numbers in the formula. In our example:
   • 2B + Ph = (2 * 20) + (18 * 3) = 40 + 54 = 94.

Tips

• A rectangular prism is a type of cuboid, which is a geometric term for a dense figure with six sides, making it a type of convex polyhedron.
• Finding the area of ​​a rectangular prism can be more convenient than you think in real life - cabinets, doors, rooms, etc., are often rectangular prisms, which means you may need to calculate their area for DIY projects around the house.
• Finding the area of ​​a rectangular prism may seem difficult, but it is not that difficult once you get the hang of the formula. Practice finding the surface using the formula 2B + Ph several times to get the hang of it.