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Finding the Fourth Proportional to 138.30, 190.84 and 85.86

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Solution

The fourth proportional to 138.30, 190.84 and 85.86 is: 118.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.30 : 190.84 = 85.86 : x
  2. Step 2: Convert to fraction form
    138.30/190.84 = 85.86/x
  3. Step 3: Cross multiply
    138.30x = 190.84 × 85.86
  4. Step 4: Simplify right side
    138.30x = 16,385.52
  5. Step 5: Solve for x
    x = 16,385.52/138.30
  6. Step 6: Final answer
    x = 118.48

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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.