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Finding the Fourth Proportional to 427.67, 641.49 and 139.11

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Solution

The fourth proportional to 427.67, 641.49 and 139.11 is: 208.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.67 : 641.49 = 139.11 : x
  2. Step 2: Convert to fraction form
    427.67/641.49 = 139.11/x
  3. Step 3: Cross multiply
    427.67x = 641.49 × 139.11
  4. Step 4: Simplify right side
    427.67x = 89,237.67
  5. Step 5: Solve for x
    x = 89,237.67/427.67
  6. Step 6: Final answer
    x = 208.66

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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.