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Finding the Fourth Proportional to 20.38, 30.70 and 18.38

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Solution

The fourth proportional to 20.38, 30.70 and 18.38 is: 27.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.38 : 30.70 = 18.38 : x
  2. Step 2: Convert to fraction form
    20.38/30.70 = 18.38/x
  3. Step 3: Cross multiply
    20.38x = 30.70 × 18.38
  4. Step 4: Simplify right side
    20.38x = 564.02
  5. Step 5: Solve for x
    x = 564.02/20.38
  6. Step 6: Final answer
    x = 27.67

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.