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Finding the Fourth Proportional to 12.40, 17.20 and 11.65

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Solution

The fourth proportional to 12.40, 17.20 and 11.65 is: 16.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.40 : 17.20 = 11.65 : x
  2. Step 2: Convert to fraction form
    12.40/17.20 = 11.65/x
  3. Step 3: Cross multiply
    12.40x = 17.20 × 11.65
  4. Step 4: Simplify right side
    12.40x = 200.38
  5. Step 5: Solve for x
    x = 200.38/12.40
  6. Step 6: Final answer
    x = 16.16

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.