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Finding the Fourth Proportional to 137.42, 189.62 and 87.61

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Solution

The fourth proportional to 137.42, 189.62 and 87.61 is: 120.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.42 : 189.62 = 87.61 : x
  2. Step 2: Convert to fraction form
    137.42/189.62 = 87.61/x
  3. Step 3: Cross multiply
    137.42x = 189.62 × 87.61
  4. Step 4: Simplify right side
    137.42x = 16,612.74
  5. Step 5: Solve for x
    x = 16,612.74/137.42
  6. Step 6: Final answer
    x = 120.89

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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.