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Finding the Fourth Proportional to 861.80, 1,189.31 and 488.76

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Solution

The fourth proportional to 861.80, 1,189.31 and 488.76 is: 674.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.80 : 1,189.31 = 488.76 : x
  2. Step 2: Convert to fraction form
    861.80/1,189.31 = 488.76/x
  3. Step 3: Cross multiply
    861.80x = 1,189.31 × 488.76
  4. Step 4: Simplify right side
    861.80x = 581,287.16
  5. Step 5: Solve for x
    x = 581,287.16/861.80
  6. Step 6: Final answer
    x = 674.50

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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.