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Finding the Fourth Proportional to 861.87, 1,292.49 and 313.89

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Solution

The fourth proportional to 861.87, 1,292.49 and 313.89 is: 470.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.87 : 1,292.49 = 313.89 : x
  2. Step 2: Convert to fraction form
    861.87/1,292.49 = 313.89/x
  3. Step 3: Cross multiply
    861.87x = 1,292.49 × 313.89
  4. Step 4: Simplify right side
    861.87x = 405,699.69
  5. Step 5: Solve for x
    x = 405,699.69/861.87
  6. Step 6: Final answer
    x = 470.72

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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.