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Finding the Fourth Proportional to 319.20, 478.40 and 136.38

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Solution

The fourth proportional to 319.20, 478.40 and 136.38 is: 204.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    319.20 : 478.40 = 136.38 : x
  2. Step 2: Convert to fraction form
    319.20/478.40 = 136.38/x
  3. Step 3: Cross multiply
    319.20x = 478.40 × 136.38
  4. Step 4: Simplify right side
    319.20x = 65,243.85
  5. Step 5: Solve for x
    x = 65,243.85/319.20
  6. Step 6: Final answer
    x = 204.40

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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.