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Finding the Fourth Proportional to 139.62, 192.63 and 87.15

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Solution

The fourth proportional to 139.62, 192.63 and 87.15 is: 120.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.62 : 192.63 = 87.15 : x
  2. Step 2: Convert to fraction form
    139.62/192.63 = 87.15/x
  3. Step 3: Cross multiply
    139.62x = 192.63 × 87.15
  4. Step 4: Simplify right side
    139.62x = 16,787.70
  5. Step 5: Solve for x
    x = 16,787.70/139.62
  6. Step 6: Final answer
    x = 120.24

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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.