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Finding the Fourth Proportional to 725.78, 1,089.14 and 315.11

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Solution

The fourth proportional to 725.78, 1,089.14 and 315.11 is: 472.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    725.78 : 1,089.14 = 315.11 : x
  2. Step 2: Convert to fraction form
    725.78/1,089.14 = 315.11/x
  3. Step 3: Cross multiply
    725.78x = 1,089.14 × 315.11
  4. Step 4: Simplify right side
    725.78x = 343,191.88
  5. Step 5: Solve for x
    x = 343,191.88/725.78
  6. Step 6: Final answer
    x = 472.86

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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.