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Finding the Fourth Proportional to 862.70, 1,190.60 and 489.78

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Solution

The fourth proportional to 862.70, 1,190.60 and 489.78 is: 675.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    862.70 : 1,190.60 = 489.78 : x
  2. Step 2: Convert to fraction form
    862.70/1,190.60 = 489.78/x
  3. Step 3: Cross multiply
    862.70x = 1,190.60 × 489.78
  4. Step 4: Simplify right side
    862.70x = 583,132.07
  5. Step 5: Solve for x
    x = 583,132.07/862.70
  6. Step 6: Final answer
    x = 675.94

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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.