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Finding the Fourth Proportional to 139.39, 192.28 and 87.55

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Solution

The fourth proportional to 139.39, 192.28 and 87.55 is: 120.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.39 : 192.28 = 87.55 : x
  2. Step 2: Convert to fraction form
    139.39/192.28 = 87.55/x
  3. Step 3: Cross multiply
    139.39x = 192.28 × 87.55
  4. Step 4: Simplify right side
    139.39x = 16,834.11
  5. Step 5: Solve for x
    x = 16,834.11/139.39
  6. Step 6: Final answer
    x = 120.77

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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.