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Finding the Fourth Proportional to 394.47, 545.13 and 311.45

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Solution

The fourth proportional to 394.47, 545.13 and 311.45 is: 430.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    394.47 : 545.13 = 311.45 : x
  2. Step 2: Convert to fraction form
    394.47/545.13 = 311.45/x
  3. Step 3: Cross multiply
    394.47x = 545.13 × 311.45
  4. Step 4: Simplify right side
    394.47x = 169,778.01
  5. Step 5: Solve for x
    x = 169,778.01/394.47
  6. Step 6: Final answer
    x = 430.40

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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.