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Finding the Fourth Proportional to 15.71, 21.72 and 12.47

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Solution

The fourth proportional to 15.71, 21.72 and 12.47 is: 17.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.71 : 21.72 = 12.47 : x
  2. Step 2: Convert to fraction form
    15.71/21.72 = 12.47/x
  3. Step 3: Cross multiply
    15.71x = 21.72 × 12.47
  4. Step 4: Simplify right side
    15.71x = 270.79
  5. Step 5: Solve for x
    x = 270.79/15.71
  6. Step 6: Final answer
    x = 17.24

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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.