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Finding the Fourth Proportional to 1,387.90, 2,081.87 and 414.05

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Solution

The fourth proportional to 1,387.90, 2,081.87 and 414.05 is: 621.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.90 : 2,081.87 = 414.05 : x
  2. Step 2: Convert to fraction form
    1,387.90/2,081.87 = 414.05/x
  3. Step 3: Cross multiply
    1,387.90x = 2,081.87 × 414.05
  4. Step 4: Simplify right side
    1,387.90x = 861,987.35
  5. Step 5: Solve for x
    x = 861,987.35/1,387.90
  6. Step 6: Final answer
    x = 621.07

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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.