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Finding the Fourth Proportional to 13.18, 19.64 and 12.85

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Solution

The fourth proportional to 13.18, 19.64 and 12.85 is: 19.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.18 : 19.64 = 12.85 : x
  2. Step 2: Convert to fraction form
    13.18/19.64 = 12.85/x
  3. Step 3: Cross multiply
    13.18x = 19.64 × 12.85
  4. Step 4: Simplify right side
    13.18x = 252.37
  5. Step 5: Solve for x
    x = 252.37/13.18
  6. Step 6: Final answer
    x = 19.15

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.