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Finding the Fourth Proportional to 13.58, 18.72 and 12.21

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Solution

The fourth proportional to 13.58, 18.72 and 12.21 is: 16.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.58 : 18.72 = 12.21 : x
  2. Step 2: Convert to fraction form
    13.58/18.72 = 12.21/x
  3. Step 3: Cross multiply
    13.58x = 18.72 × 12.21
  4. Step 4: Simplify right side
    13.58x = 228.48
  5. Step 5: Solve for x
    x = 228.48/13.58
  6. Step 6: Final answer
    x = 16.83

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.