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Finding the Fourth Proportional to 831.87, 1,147.37 and 645.17

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Solution

The fourth proportional to 831.87, 1,147.37 and 645.17 is: 889.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.87 : 1,147.37 = 645.17 : x
  2. Step 2: Convert to fraction form
    831.87/1,147.37 = 645.17/x
  3. Step 3: Cross multiply
    831.87x = 1,147.37 × 645.17
  4. Step 4: Simplify right side
    831.87x = 740,239.74
  5. Step 5: Solve for x
    x = 740,239.74/831.87
  6. Step 6: Final answer
    x = 889.85

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.