Surface Area Comparison: 1x2x3 vs 2x1x3 Rectangular Prisms

Question

Are the surface areas of the two orthohedrons below the same or different?

111222333222111333

Video Solution

Solution Steps

00:00 Are the surface areas equal?
00:03 Now we'll use the formula for calculating the surface area of a box
00:07 2 times the sum of face areas
00:18 Let's substitute appropriate values for each box
00:50 Let's compare the side values, and we'll see they are equal
00:57 Boxes with equal edges have equal surface areas
01:02 And this is the solution to the question

Step-by-Step Solution

To solve the problem, we'll proceed through these steps:

  • Step 1: Identify the dimensions of the orthohedrons from the diagram.
  • Step 2: Apply the surface area formula for a cuboid.
  • Step 3: Compare the surface areas to determine if they are equal or different.

Step 1: Dimensions from the diagram:

  • Orthohedron 1: Length l=3 l = 3 , Width w=2 w = 2 , Height h=1 h = 1 .
  • Orthohedron 2: Length l=2 l = 2 , Width w=3 w = 3 , Height h=1 h = 1 .

Step 2: Calculate surface areas using the formula SA=2(lw+lh+wh) SA = 2(lw + lh + wh) .

For Orthohedron 1:
SA1=2(32+31+21)=2(6+3+2)=2(11)=22 SA_1 = 2(3 \cdot 2 + 3 \cdot 1 + 2 \cdot 1) = 2(6 + 3 + 2) = 2(11) = 22 .

For Orthohedron 2:
SA2=2(23+21+31)=2(6+2+3)=2(11)=22 SA_2 = 2(2 \cdot 3 + 2 \cdot 1 + 3 \cdot 1) = 2(6 + 2 + 3) = 2(11) = 22 .

Step 3: Compare the surface areas:
Both orthohedrons have a surface area of 22; therefore, the surface areas are equal.

Thus, the surface areas of the two orthohedrons are equal.

The correct answer is: = = .

Answer

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