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Finding the Fourth Proportional to 15.66, 21.56 and 13.23

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Solution

The fourth proportional to 15.66, 21.56 and 13.23 is: 18.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.66 : 21.56 = 13.23 : x
  2. Step 2: Convert to fraction form
    15.66/21.56 = 13.23/x
  3. Step 3: Cross multiply
    15.66x = 21.56 × 13.23
  4. Step 4: Simplify right side
    15.66x = 285.17
  5. Step 5: Solve for x
    x = 285.17/15.66
  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.