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video tutorial formula for surface area rectangular prism
prism 3x4x6

Find the surface area of a rectangular prism with the dimensions of 5 by 5 by 4 units.

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Surface area of a rectangular prism formula

Method 2.

​Formula for surface area = P x h + 2B

Step 1. If you unfolded the prism, the sides would look like this.
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  • P = Perimeter of the prism
  • h = height of the prism
  • B = base area
​Method 2. Use the formula 

                 P x h + 2B

formula for surface area rectangular prism graphic

Finding the surface area of a rectangular prism

Find the surface area of a rectangular prism with the dimensions of 6 by 4 by 3 units.

Method 1.

Step 1. Multiply length times width of the front and back side  6 x 3 = 18 

Multiply 18 by two because there is a front and a back side.           18 x 2 = 36

Step 2. Repeat for the two ends and the top and bottom of the rectangular prism

4 x3 = 12
 12 x 2 = 24

6 x 4 = 24
 24 x 2 = 48
Step 3. Add these three areas together for the total surface area

36 + 24 + 48 = 108 square units
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6
4
4
6
Add these four sides together for the perimeter

6 + 4 + 6 + 4 = 20
Step 2. Multiply the Perimeter times the height

20 x 3 = 60

Step 3. Compute your base areas 6 x 4 =24
                Multiply your base area times two for your total base area   24 x 2 = 48
Step 4. Add your perimeter area to your total base area for your total surface area

              48 + 60 = 108 square units


Method 1. Add area of each side together
                      5 x5 = 25 x 2 = 50
                      5 x4 = 20 x 2 = 40
                      5 x 5 = 25 x 2 = 50
Add these side areas for total surface area 
50 + 40 + 50  = 140 square units
Method 2
Step 1. Find the perimeter
​5 + 4 + 5 + 4 = 18

Step 2. Multiply P x h
18 x 5 = 90

Step 3. Add perimeter to area of two bases

90 + 2(5 x5 ) = 90 + 50 = 140 units squared



5x5x4 prism
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Front/Back Area
Top/Bottom Area
End/End Area

Finding the surface area of a rectangular prism calculator

Formula for surface area of a rectangular prism video answer.

​Method 1. You can add the area of each pair of sides of the rectangular prism.