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Finding the Fourth Proportional to 12.45, 17.18 and 7.85

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Solution

The fourth proportional to 12.45, 17.18 and 7.85 is: 10.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.45 : 17.18 = 7.85 : x
  2. Step 2: Convert to fraction form
    12.45/17.18 = 7.85/x
  3. Step 3: Cross multiply
    12.45x = 17.18 × 7.85
  4. Step 4: Simplify right side
    12.45x = 134.74
  5. Step 5: Solve for x
    x = 134.74/12.45
  6. Step 6: Final answer
    x = 10.82

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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.