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Finding the Fourth Proportional to 861.12, 1,291.50 and 340.92

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Solution

The fourth proportional to 861.12, 1,291.50 and 340.92 is: 511.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.12 : 1,291.50 = 340.92 : x
  2. Step 2: Convert to fraction form
    861.12/1,291.50 = 340.92/x
  3. Step 3: Cross multiply
    861.12x = 1,291.50 × 340.92
  4. Step 4: Simplify right side
    861.12x = 440,298.18
  5. Step 5: Solve for x
    x = 440,298.18/861.12
  6. Step 6: Final answer
    x = 511.31

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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.