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Finding the Fourth Proportional to 1,138.70, 1,708.45 and 408.30

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Solution

The fourth proportional to 1,138.70, 1,708.45 and 408.30 is: 612.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.70 : 1,708.45 = 408.30 : x
  2. Step 2: Convert to fraction form
    1,138.70/1,708.45 = 408.30/x
  3. Step 3: Cross multiply
    1,138.70x = 1,708.45 × 408.30
  4. Step 4: Simplify right side
    1,138.70x = 697,560.14
  5. Step 5: Solve for x
    x = 697,560.14/1,138.70
  6. Step 6: Final answer
    x = 612.59

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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.