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Finding the Fourth Proportional to 15.38, 21.18 and 15.20

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Solution

The fourth proportional to 15.38, 21.18 and 15.20 is: 20.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.38 : 21.18 = 15.20 : x
  2. Step 2: Convert to fraction form
    15.38/21.18 = 15.20/x
  3. Step 3: Cross multiply
    15.38x = 21.18 × 15.20
  4. Step 4: Simplify right side
    15.38x = 321.97
  5. Step 5: Solve for x
    x = 321.97/15.38
  6. Step 6: Final answer
    x = 20.94

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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.