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Finding the Fourth Proportional to 427.55, 641.11 and 138.95

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Solution

The fourth proportional to 427.55, 641.11 and 138.95 is: 208.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.55 : 641.11 = 138.95 : x
  2. Step 2: Convert to fraction form
    427.55/641.11 = 138.95/x
  3. Step 3: Cross multiply
    427.55x = 641.11 × 138.95
  4. Step 4: Simplify right side
    427.55x = 89,082.23
  5. Step 5: Solve for x
    x = 89,082.23/427.55
  6. Step 6: Final answer
    x = 208.36

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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.