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Finding the Fourth Proportional to 26.60, 39.90 and 12.88

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Solution

The fourth proportional to 26.60, 39.90 and 12.88 is: 19.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    26.60 : 39.90 = 12.88 : x
  2. Step 2: Convert to fraction form
    26.60/39.90 = 12.88/x
  3. Step 3: Cross multiply
    26.60x = 39.90 × 12.88
  4. Step 4: Simplify right side
    26.60x = 513.91
  5. Step 5: Solve for x
    x = 513.91/26.60
  6. Step 6: Final answer
    x = 19.32

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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.