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Finding the Fourth Proportional to 138.82, 191.54 and 87.08

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Solution

The fourth proportional to 138.82, 191.54 and 87.08 is: 120.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.82 : 191.54 = 87.08 : x
  2. Step 2: Convert to fraction form
    138.82/191.54 = 87.08/x
  3. Step 3: Cross multiply
    138.82x = 191.54 × 87.08
  4. Step 4: Simplify right side
    138.82x = 16,679.30
  5. Step 5: Solve for x
    x = 16,679.30/138.82
  6. Step 6: Final answer
    x = 120.15

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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.