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Finding the Fourth Proportional to 30.76, 42.44 and 20.39

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Solution

The fourth proportional to 30.76, 42.44 and 20.39 is: 28.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.76 : 42.44 = 20.39 : x
  2. Step 2: Convert to fraction form
    30.76/42.44 = 20.39/x
  3. Step 3: Cross multiply
    30.76x = 42.44 × 20.39
  4. Step 4: Simplify right side
    30.76x = 865.31
  5. Step 5: Solve for x
    x = 865.31/30.76
  6. Step 6: Final answer
    x = 28.13

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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.