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Finding the Fourth Proportional to 427.38, 641.06 and 138.81

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Solution

The fourth proportional to 427.38, 641.06 and 138.81 is: 208.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.38 : 641.06 = 138.81 : x
  2. Step 2: Convert to fraction form
    427.38/641.06 = 138.81/x
  3. Step 3: Cross multiply
    427.38x = 641.06 × 138.81
  4. Step 4: Simplify right side
    427.38x = 88,985.54
  5. Step 5: Solve for x
    x = 88,985.54/427.38
  6. Step 6: Final answer
    x = 208.21

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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.