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Finding the Fourth Proportional to 136.80, 205.15 and 39.28

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Solution

The fourth proportional to 136.80, 205.15 and 39.28 is: 58.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.80 : 205.15 = 39.28 : x
  2. Step 2: Convert to fraction form
    136.80/205.15 = 39.28/x
  3. Step 3: Cross multiply
    136.80x = 205.15 × 39.28
  4. Step 4: Simplify right side
    136.80x = 8,058.38
  5. Step 5: Solve for x
    x = 8,058.38/136.80
  6. Step 6: Final answer
    x = 58.90

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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.