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Finding the Fourth Proportional to 387.70, 535.35 and 257.29

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Solution

The fourth proportional to 387.70, 535.35 and 257.29 is: 355.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.70 : 535.35 = 257.29 : x
  2. Step 2: Convert to fraction form
    387.70/535.35 = 257.29/x
  3. Step 3: Cross multiply
    387.70x = 535.35 × 257.29
  4. Step 4: Simplify right side
    387.70x = 137,740.20
  5. Step 5: Solve for x
    x = 137,740.20/387.70
  6. Step 6: Final answer
    x = 355.28

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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.