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Finding the Fourth Proportional to 831.69, 1,247.67 and 398.79

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Solution

The fourth proportional to 831.69, 1,247.67 and 398.79 is: 598.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.69 : 1,247.67 = 398.79 : x
  2. Step 2: Convert to fraction form
    831.69/1,247.67 = 398.79/x
  3. Step 3: Cross multiply
    831.69x = 1,247.67 × 398.79
  4. Step 4: Simplify right side
    831.69x = 497,558.32
  5. Step 5: Solve for x
    x = 497,558.32/831.69
  6. Step 6: Final answer
    x = 598.25

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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.