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Finding the Fourth Proportional to 756.78, 1,135 and 391.38

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Solution

The fourth proportional to 756.78, 1,135 and 391.38 is: 586.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    756.78 : 1,135 = 391.38 : x
  2. Step 2: Convert to fraction form
    756.78/1,135 = 391.38/x
  3. Step 3: Cross multiply
    756.78x = 1,135 × 391.38
  4. Step 4: Simplify right side
    756.78x = 444,216.30
  5. Step 5: Solve for x
    x = 444,216.30/756.78
  6. Step 6: Final answer
    x = 586.98

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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.