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Finding the Fourth Proportional to 638.24, 879.72 and 490.64

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Solution

The fourth proportional to 638.24, 879.72 and 490.64 is: 676.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.24 : 879.72 = 490.64 : x
  2. Step 2: Convert to fraction form
    638.24/879.72 = 490.64/x
  3. Step 3: Cross multiply
    638.24x = 879.72 × 490.64
  4. Step 4: Simplify right side
    638.24x = 431,625.82
  5. Step 5: Solve for x
    x = 431,625.82/638.24
  6. Step 6: Final answer
    x = 676.28

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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.