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Finding the Fourth Proportional to 11.15, 15.38 and 7.65

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Solution

The fourth proportional to 11.15, 15.38 and 7.65 is: 10.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    11.15 : 15.38 = 7.65 : x
  2. Step 2: Convert to fraction form
    11.15/15.38 = 7.65/x
  3. Step 3: Cross multiply
    11.15x = 15.38 × 7.65
  4. Step 4: Simplify right side
    11.15x = 117.71
  5. Step 5: Solve for x
    x = 117.71/11.15
  6. Step 6: Final answer
    x = 10.56

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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.