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Finding the Fourth Proportional to 12.85, 19.26 and 12.40

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Solution

The fourth proportional to 12.85, 19.26 and 12.40 is: 18.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.85 : 19.26 = 12.40 : x
  2. Step 2: Convert to fraction form
    12.85/19.26 = 12.40/x
  3. Step 3: Cross multiply
    12.85x = 19.26 × 12.40
  4. Step 4: Simplify right side
    12.85x = 238.82
  5. Step 5: Solve for x
    x = 238.82/12.85
  6. Step 6: Final answer
    x = 18.59

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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.