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Finding the Fourth Proportional to 12.40, 17.12 and 8.78

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Solution

The fourth proportional to 12.40, 17.12 and 8.78 is: 12.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.40 : 17.12 = 8.78 : x
  2. Step 2: Convert to fraction form
    12.40/17.12 = 8.78/x
  3. Step 3: Cross multiply
    12.40x = 17.12 × 8.78
  4. Step 4: Simplify right side
    12.40x = 150.31
  5. Step 5: Solve for x
    x = 150.31/12.40
  6. Step 6: Final answer
    x = 12.12

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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.