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Finding the Fourth Proportional to 728, 1,092 and 215

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Solution

The fourth proportional to 728, 1,092 and 215 is: 322.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    728 : 1,092 = 215 : x
  2. Step 2: Convert to fraction form
    728/1,092 = 215/x
  3. Step 3: Cross multiply
    728x = 1,092 × 215
  4. Step 4: Simplify right side
    728x = 234,780
  5. Step 5: Solve for x
    x = 234,780/728
  6. Step 6: Final answer
    x = 322.50

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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.