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Finding the Fourth Proportional to 1,387.72, 2,081.96 and 521.56

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Solution

The fourth proportional to 1,387.72, 2,081.96 and 521.56 is: 782.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.72 : 2,081.96 = 521.56 : x
  2. Step 2: Convert to fraction form
    1,387.72/2,081.96 = 521.56/x
  3. Step 3: Cross multiply
    1,387.72x = 2,081.96 × 521.56
  4. Step 4: Simplify right side
    1,387.72x = 1,085,867.06
  5. Step 5: Solve for x
    x = 1,085,867.06/1,387.72
  6. Step 6: Final answer
    x = 782.48

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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.