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Finding the Fourth Proportional to 26.40, 39.61 and 12.87

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Solution

The fourth proportional to 26.40, 39.61 and 12.87 is: 19.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    26.40 : 39.61 = 12.87 : x
  2. Step 2: Convert to fraction form
    26.40/39.61 = 12.87/x
  3. Step 3: Cross multiply
    26.40x = 39.61 × 12.87
  4. Step 4: Simplify right side
    26.40x = 509.90
  5. Step 5: Solve for x
    x = 509.90/26.40
  6. Step 6: Final answer
    x = 19.31

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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.