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Finding the Fourth Proportional to 15.25, 21 and 13.71

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Solution

The fourth proportional to 15.25, 21 and 13.71 is: 18.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.25 : 21 = 13.71 : x
  2. Step 2: Convert to fraction form
    15.25/21 = 13.71/x
  3. Step 3: Cross multiply
    15.25x = 21 × 13.71
  4. Step 4: Simplify right side
    15.25x = 287.91
  5. Step 5: Solve for x
    x = 287.91/15.25
  6. Step 6: Final answer
    x = 18.88

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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.