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Finding the Fourth Proportional to 862.20, 1,189.85 and 489.11

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Solution

The fourth proportional to 862.20, 1,189.85 and 489.11 is: 674.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    862.20 : 1,189.85 = 489.11 : x
  2. Step 2: Convert to fraction form
    862.20/1,189.85 = 489.11/x
  3. Step 3: Cross multiply
    862.20x = 1,189.85 × 489.11
  4. Step 4: Simplify right side
    862.20x = 581,959.14
  5. Step 5: Solve for x
    x = 581,959.14/862.20
  6. Step 6: Final answer
    x = 674.97

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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.