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Finding the Fourth Proportional to 139.12, 191.95 and 86.64

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Solution

The fourth proportional to 139.12, 191.95 and 86.64 is: 119.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.12 : 191.95 = 86.64 : x
  2. Step 2: Convert to fraction form
    139.12/191.95 = 86.64/x
  3. Step 3: Cross multiply
    139.12x = 191.95 × 86.64
  4. Step 4: Simplify right side
    139.12x = 16,630.55
  5. Step 5: Solve for x
    x = 16,630.55/139.12
  6. Step 6: Final answer
    x = 119.54

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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.