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Finding the Fourth Proportional to 387.92, 535.56 and 257.20

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Solution

The fourth proportional to 387.92, 535.56 and 257.20 is: 355.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.92 : 535.56 = 257.20 : x
  2. Step 2: Convert to fraction form
    387.92/535.56 = 257.20/x
  3. Step 3: Cross multiply
    387.92x = 535.56 × 257.20
  4. Step 4: Simplify right side
    387.92x = 137,746.03
  5. Step 5: Solve for x
    x = 137,746.03/387.92
  6. Step 6: Final answer
    x = 355.09

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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.