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Finding the Fourth Proportional to 427.80, 641.76 and 135.38

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Solution

The fourth proportional to 427.80, 641.76 and 135.38 is: 203.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.80 : 641.76 = 135.38 : x
  2. Step 2: Convert to fraction form
    427.80/641.76 = 135.38/x
  3. Step 3: Cross multiply
    427.80x = 641.76 × 135.38
  4. Step 4: Simplify right side
    427.80x = 86,882.58
  5. Step 5: Solve for x
    x = 86,882.58/427.80
  6. Step 6: Final answer
    x = 203.09

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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.