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Finding the Fourth Proportional to 15.92, 21.96 and 13.20

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Solution

The fourth proportional to 15.92, 21.96 and 13.20 is: 18.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.92 : 21.96 = 13.20 : x
  2. Step 2: Convert to fraction form
    15.92/21.96 = 13.20/x
  3. Step 3: Cross multiply
    15.92x = 21.96 × 13.20
  4. Step 4: Simplify right side
    15.92x = 289.87
  5. Step 5: Solve for x
    x = 289.87/15.92
  6. Step 6: Final answer
    x = 18.21

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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.