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Finding the Fourth Proportional to 1,187.87, 1,781.78 and 407.88

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Solution

The fourth proportional to 1,187.87, 1,781.78 and 407.88 is: 611.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,187.87 : 1,781.78 = 407.88 : x
  2. Step 2: Convert to fraction form
    1,187.87/1,781.78 = 407.88/x
  3. Step 3: Cross multiply
    1,187.87x = 1,781.78 × 407.88
  4. Step 4: Simplify right side
    1,187.87x = 726,753.45
  5. Step 5: Solve for x
    x = 726,753.45/1,187.87
  6. Step 6: Final answer
    x = 611.81

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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.