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Finding the Fourth Proportional to 137.70, 205.61 and 128.34

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Solution

The fourth proportional to 137.70, 205.61 and 128.34 is: 191.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.70 : 205.61 = 128.34 : x
  2. Step 2: Convert to fraction form
    137.70/205.61 = 128.34/x
  3. Step 3: Cross multiply
    137.70x = 205.61 × 128.34
  4. Step 4: Simplify right side
    137.70x = 26,387.35
  5. Step 5: Solve for x
    x = 26,387.35/137.70
  6. Step 6: Final answer
    x = 191.63

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.