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Finding the Fourth Proportional to 28.39, 39.18 and 19.66

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Solution

The fourth proportional to 28.39, 39.18 and 19.66 is: 27.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.39 : 39.18 = 19.66 : x
  2. Step 2: Convert to fraction form
    28.39/39.18 = 19.66/x
  3. Step 3: Cross multiply
    28.39x = 39.18 × 19.66
  4. Step 4: Simplify right side
    28.39x = 770.28
  5. Step 5: Solve for x
    x = 770.28/28.39
  6. Step 6: Final answer
    x = 27.13

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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.