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Finding the Fourth Proportional to 13.15, 19.72 and 8.11

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Solution

The fourth proportional to 13.15, 19.72 and 8.11 is: 12.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.15 : 19.72 = 8.11 : x
  2. Step 2: Convert to fraction form
    13.15/19.72 = 8.11/x
  3. Step 3: Cross multiply
    13.15x = 19.72 × 8.11
  4. Step 4: Simplify right side
    13.15x = 159.86
  5. Step 5: Solve for x
    x = 159.86/13.15
  6. Step 6: Final answer
    x = 12.16

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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.