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Finding the Fourth Proportional to 545.78, 820.28 and 257.42

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Solution

The fourth proportional to 545.78, 820.28 and 257.42 is: 386.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    545.78 : 820.28 = 257.42 : x
  2. Step 2: Convert to fraction form
    545.78/820.28 = 257.42/x
  3. Step 3: Cross multiply
    545.78x = 820.28 × 257.42
  4. Step 4: Simplify right side
    545.78x = 211,151.09
  5. Step 5: Solve for x
    x = 211,151.09/545.78
  6. Step 6: Final answer
    x = 386.88

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.