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Finding the Fourth Proportional to 861.69, 1,189.31 and 512.31

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Solution

The fourth proportional to 861.69, 1,189.31 and 512.31 is: 707.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.69 : 1,189.31 = 512.31 : x
  2. Step 2: Convert to fraction form
    861.69/1,189.31 = 512.31/x
  3. Step 3: Cross multiply
    861.69x = 1,189.31 × 512.31
  4. Step 4: Simplify right side
    861.69x = 609,292.84
  5. Step 5: Solve for x
    x = 609,292.84/861.69
  6. Step 6: Final answer
    x = 707.09

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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.