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Finding the Fourth Proportional to 1,138.56, 1,708.80 and 489.78

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Solution

The fourth proportional to 1,138.56, 1,708.80 and 489.78 is: 735.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.56 : 1,708.80 = 489.78 : x
  2. Step 2: Convert to fraction form
    1,138.56/1,708.80 = 489.78/x
  3. Step 3: Cross multiply
    1,138.56x = 1,708.80 × 489.78
  4. Step 4: Simplify right side
    1,138.56x = 836,936.06
  5. Step 5: Solve for x
    x = 836,936.06/1,138.56
  6. Step 6: Final answer
    x = 735.08

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.