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Finding the Fourth Proportional to 15.15, 20.91 and 11.51

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Solution

The fourth proportional to 15.15, 20.91 and 11.51 is: 15.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.15 : 20.91 = 11.51 : x
  2. Step 2: Convert to fraction form
    15.15/20.91 = 11.51/x
  3. Step 3: Cross multiply
    15.15x = 20.91 × 11.51
  4. Step 4: Simplify right side
    15.15x = 240.57
  5. Step 5: Solve for x
    x = 240.57/15.15
  6. Step 6: Final answer
    x = 15.88

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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.