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Finding the Fourth Proportional to 394.80, 545.40 and 308.60

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Solution

The fourth proportional to 394.80, 545.40 and 308.60 is: 426.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    394.80 : 545.40 = 308.60 : x
  2. Step 2: Convert to fraction form
    394.80/545.40 = 308.60/x
  3. Step 3: Cross multiply
    394.80x = 545.40 × 308.60
  4. Step 4: Simplify right side
    394.80x = 168,310.44
  5. Step 5: Solve for x
    x = 168,310.44/394.80
  6. Step 6: Final answer
    x = 426.32

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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.