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Finding the Fourth Proportional to 19.72, 29.56 and 13.20

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Solution

The fourth proportional to 19.72, 29.56 and 13.20 is: 19.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    19.72 : 29.56 = 13.20 : x
  2. Step 2: Convert to fraction form
    19.72/29.56 = 13.20/x
  3. Step 3: Cross multiply
    19.72x = 29.56 × 13.20
  4. Step 4: Simplify right side
    19.72x = 390.19
  5. Step 5: Solve for x
    x = 390.19/19.72
  6. Step 6: Final answer
    x = 19.79

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.