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Finding the Fourth Proportional to 831.90, 1,247.88 and 215.58

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Solution

The fourth proportional to 831.90, 1,247.88 and 215.58 is: 323.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.90 : 1,247.88 = 215.58 : x
  2. Step 2: Convert to fraction form
    831.90/1,247.88 = 215.58/x
  3. Step 3: Cross multiply
    831.90x = 1,247.88 × 215.58
  4. Step 4: Simplify right side
    831.90x = 269,017.97
  5. Step 5: Solve for x
    x = 269,017.97/831.90
  6. Step 6: Final answer
    x = 323.38

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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.