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Finding the Fourth Proportional to 139.45, 192.45 and 77.28

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Solution

The fourth proportional to 139.45, 192.45 and 77.28 is: 106.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.45 : 192.45 = 77.28 : x
  2. Step 2: Convert to fraction form
    139.45/192.45 = 77.28/x
  3. Step 3: Cross multiply
    139.45x = 192.45 × 77.28
  4. Step 4: Simplify right side
    139.45x = 14,872.15
  5. Step 5: Solve for x
    x = 14,872.15/139.45
  6. Step 6: Final answer
    x = 106.65

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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.