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Finding the Fourth Proportional to 203.65, 305.46 and 81.90

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Solution

The fourth proportional to 203.65, 305.46 and 81.90 is: 122.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    203.65 : 305.46 = 81.90 : x
  2. Step 2: Convert to fraction form
    203.65/305.46 = 81.90/x
  3. Step 3: Cross multiply
    203.65x = 305.46 × 81.90
  4. Step 4: Simplify right side
    203.65x = 25,017.17
  5. Step 5: Solve for x
    x = 25,017.17/203.65
  6. Step 6: Final answer
    x = 122.85

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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.