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Finding the Fourth Proportional to 861.38, 1,291.01 and 398.53

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Solution

The fourth proportional to 861.38, 1,291.01 and 398.53 is: 597.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.38 : 1,291.01 = 398.53 : x
  2. Step 2: Convert to fraction form
    861.38/1,291.01 = 398.53/x
  3. Step 3: Cross multiply
    861.38x = 1,291.01 × 398.53
  4. Step 4: Simplify right side
    861.38x = 514,506.22
  5. Step 5: Solve for x
    x = 514,506.22/861.38
  6. Step 6: Final answer
    x = 597.30

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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.