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Finding the Fourth Proportional to 427.97, 641.79 and 139.40

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Solution

The fourth proportional to 427.97, 641.79 and 139.40 is: 209.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.97 : 641.79 = 139.40 : x
  2. Step 2: Convert to fraction form
    427.97/641.79 = 139.40/x
  3. Step 3: Cross multiply
    427.97x = 641.79 × 139.40
  4. Step 4: Simplify right side
    427.97x = 89,462.32
  5. Step 5: Solve for x
    x = 89,462.32/427.97
  6. Step 6: Final answer
    x = 209.04

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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.