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Finding the Fourth Proportional to 139.17, 192.10 and 86.72

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Solution

The fourth proportional to 139.17, 192.10 and 86.72 is: 119.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.17 : 192.10 = 86.72 : x
  2. Step 2: Convert to fraction form
    139.17/192.10 = 86.72/x
  3. Step 3: Cross multiply
    139.17x = 192.10 × 86.72
  4. Step 4: Simplify right side
    139.17x = 16,658.91
  5. Step 5: Solve for x
    x = 16,658.91/139.17
  6. Step 6: Final answer
    x = 119.70

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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.