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Finding the Fourth Proportional to 861.08, 1,290.24 and 398.61

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Solution

The fourth proportional to 861.08, 1,290.24 and 398.61 is: 597.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.08 : 1,290.24 = 398.61 : x
  2. Step 2: Convert to fraction form
    861.08/1,290.24 = 398.61/x
  3. Step 3: Cross multiply
    861.08x = 1,290.24 × 398.61
  4. Step 4: Simplify right side
    861.08x = 514,302.57
  5. Step 5: Solve for x
    x = 514,302.57/861.08
  6. Step 6: Final answer
    x = 597.28

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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.