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Finding the Fourth Proportional to 137.20, 189.24 and 87.39

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Solution

The fourth proportional to 137.20, 189.24 and 87.39 is: 120.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.20 : 189.24 = 87.39 : x
  2. Step 2: Convert to fraction form
    137.20/189.24 = 87.39/x
  3. Step 3: Cross multiply
    137.20x = 189.24 × 87.39
  4. Step 4: Simplify right side
    137.20x = 16,537.68
  5. Step 5: Solve for x
    x = 16,537.68/137.20
  6. Step 6: Final answer
    x = 120.54

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.