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Finding the Fourth Proportional to 862.45, 1,189.96 and 489.31

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Solution

The fourth proportional to 862.45, 1,189.96 and 489.31 is: 675.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    862.45 : 1,189.96 = 489.31 : x
  2. Step 2: Convert to fraction form
    862.45/1,189.96 = 489.31/x
  3. Step 3: Cross multiply
    862.45x = 1,189.96 × 489.31
  4. Step 4: Simplify right side
    862.45x = 582,255.13
  5. Step 5: Solve for x
    x = 582,255.13/862.45
  6. Step 6: Final answer
    x = 675.12

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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.