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Finding the Fourth Proportional to 487.38, 671.95 and 398.76

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Solution

The fourth proportional to 487.38, 671.95 and 398.76 is: 549.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    487.38 : 671.95 = 398.76 : x
  2. Step 2: Convert to fraction form
    487.38/671.95 = 398.76/x
  3. Step 3: Cross multiply
    487.38x = 671.95 × 398.76
  4. Step 4: Simplify right side
    487.38x = 267,946.78
  5. Step 5: Solve for x
    x = 267,946.78/487.38
  6. Step 6: Final answer
    x = 549.77

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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.