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Finding the Fourth Proportional to 13.21, 18.13 and 12.87

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Solution

The fourth proportional to 13.21, 18.13 and 12.87 is: 17.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.21 : 18.13 = 12.87 : x
  2. Step 2: Convert to fraction form
    13.21/18.13 = 12.87/x
  3. Step 3: Cross multiply
    13.21x = 18.13 × 12.87
  4. Step 4: Simplify right side
    13.21x = 233.24
  5. Step 5: Solve for x
    x = 233.24/13.21
  6. Step 6: Final answer
    x = 17.66

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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.