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Finding the Fourth Proportional to 15.56, 21.38 and 13.72

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Solution

The fourth proportional to 15.56, 21.38 and 13.72 is: 18.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.56 : 21.38 = 13.72 : x
  2. Step 2: Convert to fraction form
    15.56/21.38 = 13.72/x
  3. Step 3: Cross multiply
    15.56x = 21.38 × 13.72
  4. Step 4: Simplify right side
    15.56x = 293.33
  5. Step 5: Solve for x
    x = 293.33/15.56
  6. Step 6: Final answer
    x = 18.85

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.