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Finding the Fourth Proportional to 765.78, 1,148.55 and 217.90

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Solution

The fourth proportional to 765.78, 1,148.55 and 217.90 is: 326.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    765.78 : 1,148.55 = 217.90 : x
  2. Step 2: Convert to fraction form
    765.78/1,148.55 = 217.90/x
  3. Step 3: Cross multiply
    765.78x = 1,148.55 × 217.90
  4. Step 4: Simplify right side
    765.78x = 250,269.05
  5. Step 5: Solve for x
    x = 250,269.05/765.78
  6. Step 6: Final answer
    x = 326.82

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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.