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Finding the Fourth Proportional to 427.58, 641.21 and 138.95

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Solution

The fourth proportional to 427.58, 641.21 and 138.95 is: 208.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.58 : 641.21 = 138.95 : x
  2. Step 2: Convert to fraction form
    427.58/641.21 = 138.95/x
  3. Step 3: Cross multiply
    427.58x = 641.21 × 138.95
  4. Step 4: Simplify right side
    427.58x = 89,092.23
  5. Step 5: Solve for x
    x = 89,092.23/427.58
  6. Step 6: Final answer
    x = 208.37

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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.