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Finding the Fourth Proportional to 22.31, 30.78 and 13.57

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Solution

The fourth proportional to 22.31, 30.78 and 13.57 is: 18.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    22.31 : 30.78 = 13.57 : x
  2. Step 2: Convert to fraction form
    22.31/30.78 = 13.57/x
  3. Step 3: Cross multiply
    22.31x = 30.78 × 13.57
  4. Step 4: Simplify right side
    22.31x = 417.61
  5. Step 5: Solve for x
    x = 417.61/22.31
  6. Step 6: Final answer
    x = 18.72

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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.