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Finding the Fourth Proportional to 151.20, 209.70 and 136.80

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Solution

The fourth proportional to 151.20, 209.70 and 136.80 is: 189.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    151.20 : 209.70 = 136.80 : x
  2. Step 2: Convert to fraction form
    151.20/209.70 = 136.80/x
  3. Step 3: Cross multiply
    151.20x = 209.70 × 136.80
  4. Step 4: Simplify right side
    151.20x = 28,686.96
  5. Step 5: Solve for x
    x = 28,686.96/151.20
  6. Step 6: Final answer
    x = 189.73

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.