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Finding the Fourth Proportional to 203.70, 305.30 and 81.90

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Solution

The fourth proportional to 203.70, 305.30 and 81.90 is: 122.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    203.70 : 305.30 = 81.90 : x
  2. Step 2: Convert to fraction form
    203.70/305.30 = 81.90/x
  3. Step 3: Cross multiply
    203.70x = 305.30 × 81.90
  4. Step 4: Simplify right side
    203.70x = 25,004.27
  5. Step 5: Solve for x
    x = 25,004.27/203.70
  6. Step 6: Final answer
    x = 122.75

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.