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Finding the Fourth Proportional to 20.55, 30.65 and 18.39

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Solution

The fourth proportional to 20.55, 30.65 and 18.39 is: 27.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.55 : 30.65 = 18.39 : x
  2. Step 2: Convert to fraction form
    20.55/30.65 = 18.39/x
  3. Step 3: Cross multiply
    20.55x = 30.65 × 18.39
  4. Step 4: Simplify right side
    20.55x = 563.65
  5. Step 5: Solve for x
    x = 563.65/20.55
  6. Step 6: Final answer
    x = 27.43

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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.