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Finding the Fourth Proportional to 861.88, 1,189.24 and 728.65

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Solution

The fourth proportional to 861.88, 1,189.24 and 728.65 is: 1,005.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.88 : 1,189.24 = 728.65 : x
  2. Step 2: Convert to fraction form
    861.88/1,189.24 = 728.65/x
  3. Step 3: Cross multiply
    861.88x = 1,189.24 × 728.65
  4. Step 4: Simplify right side
    861.88x = 866,539.73
  5. Step 5: Solve for x
    x = 866,539.73/861.88
  6. Step 6: Final answer
    x = 1,005.41

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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.