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Finding the Fourth Proportional to 139.42, 192.62 and 128.49

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Solution

The fourth proportional to 139.42, 192.62 and 128.49 is: 177.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.42 : 192.62 = 128.49 : x
  2. Step 2: Convert to fraction form
    139.42/192.62 = 128.49/x
  3. Step 3: Cross multiply
    139.42x = 192.62 × 128.49
  4. Step 4: Simplify right side
    139.42x = 24,749.74
  5. Step 5: Solve for x
    x = 24,749.74/139.42
  6. Step 6: Final answer
    x = 177.52

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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.