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Finding the Fourth Proportional to 1,387.59, 2,081.49 and 521.91

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Solution

The fourth proportional to 1,387.59, 2,081.49 and 521.91 is: 782.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.59 : 2,081.49 = 521.91 : x
  2. Step 2: Convert to fraction form
    1,387.59/2,081.49 = 521.91/x
  3. Step 3: Cross multiply
    1,387.59x = 2,081.49 × 521.91
  4. Step 4: Simplify right side
    1,387.59x = 1,086,350.45
  5. Step 5: Solve for x
    x = 1,086,350.45/1,387.59
  6. Step 6: Final answer
    x = 782.90

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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.