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Understanding Rectangular Prism Surface Area

May 19, 2025

Math with Mr. J: Surface Area of a Rectangular Prism

Definition of Surface Area

  • Surface Area: Total area of the outside part or layer of a 3D figure.
  • For rectangular prisms, which have six faces, calculate the area of each face and sum them to find the total surface area.

Formula for Surface Area

  • Surface Area Formula:
    • ( \text{Surface Area} = 2 \times \text{front/back} + 2 \times \text{right/left} + 2 \times \text{top/bottom} )
  • Each face pair is multiplied by 2 because opposite faces have the same area.

Calculating Surface Area

  1. Front/Back Faces:

    • Example: For the front face, use a 6 by 2 rectangle.
    • Formula: ( \text{Area} = \text{length} \times \text{width} )
    • Calculate: ( 6 \times 2 = 12 ) square inches.
    • Total for front and back: ( 2 \times 12 = 24 ) square inches.
  2. Right/Left Faces:

    • Example: For the right face, use a 3 by 2 rectangle.
    • Calculate: ( 3 \times 2 = 6 ) square inches.
    • Total for right and left: ( 2 \times 6 = 12 ) square inches.
  3. Top/Bottom Faces:

    • Example: For the top face, use a 6 by 3 rectangle.
    • Calculate: ( 6 \times 3 = 18 ) square inches.
    • Total for top and bottom: ( 2 \times 18 = 36 ) square inches.

Summing the Areas

  • Sum of all face areas:
    • Front/Back: 24 square inches
    • Right/Left: 12 square inches
    • Top/Bottom: 36 square inches
  • Total Surface Area:
    • ( 24 + 12 + 36 = 72 ) square inches.

Conclusion

  • To find the surface area of a rectangular prism, calculate the area of each face and sum them.
  • Visual aids like a net can help in understanding the layout and calculations.

Thanks for watching and learning about how to calculate the surface area of a rectangular prism. Until next time!