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Finding the Fourth Proportional to 15.51, 21.41 and 8.61

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Solution

The fourth proportional to 15.51, 21.41 and 8.61 is: 11.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.51 : 21.41 = 8.61 : x
  2. Step 2: Convert to fraction form
    15.51/21.41 = 8.61/x
  3. Step 3: Cross multiply
    15.51x = 21.41 × 8.61
  4. Step 4: Simplify right side
    15.51x = 184.27
  5. Step 5: Solve for x
    x = 184.27/15.51
  6. Step 6: Final answer
    x = 11.88

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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.