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Finding the Fourth Proportional to 20.66, 28.52 and 11.45

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Solution

The fourth proportional to 20.66, 28.52 and 11.45 is: 15.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.66 : 28.52 = 11.45 : x
  2. Step 2: Convert to fraction form
    20.66/28.52 = 11.45/x
  3. Step 3: Cross multiply
    20.66x = 28.52 × 11.45
  4. Step 4: Simplify right side
    20.66x = 326.61
  5. Step 5: Solve for x
    x = 326.61/20.66
  6. Step 6: Final answer
    x = 15.81

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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.