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Finding the Fourth Proportional to 138.45, 191.09 and 85.98

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Solution

The fourth proportional to 138.45, 191.09 and 85.98 is: 118.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.45 : 191.09 = 85.98 : x
  2. Step 2: Convert to fraction form
    138.45/191.09 = 85.98/x
  3. Step 3: Cross multiply
    138.45x = 191.09 × 85.98
  4. Step 4: Simplify right side
    138.45x = 16,429.92
  5. Step 5: Solve for x
    x = 16,429.92/138.45
  6. Step 6: Final answer
    x = 118.67

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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.