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Finding the Fourth Proportional to 427.71, 641.66 and 139.17

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Solution

The fourth proportional to 427.71, 641.66 and 139.17 is: 208.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.71 : 641.66 = 139.17 : x
  2. Step 2: Convert to fraction form
    427.71/641.66 = 139.17/x
  3. Step 3: Cross multiply
    427.71x = 641.66 × 139.17
  4. Step 4: Simplify right side
    427.71x = 89,299.13
  5. Step 5: Solve for x
    x = 89,299.13/427.71
  6. Step 6: Final answer
    x = 208.78

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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.