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Finding the Fourth Proportional to 20.38, 30.40 and 19.70

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Solution

The fourth proportional to 20.38, 30.40 and 19.70 is: 29.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.38 : 30.40 = 19.70 : x
  2. Step 2: Convert to fraction form
    20.38/30.40 = 19.70/x
  3. Step 3: Cross multiply
    20.38x = 30.40 × 19.70
  4. Step 4: Simplify right side
    20.38x = 598.88
  5. Step 5: Solve for x
    x = 598.88/20.38
  6. Step 6: Final answer
    x = 29.39

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.