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Finding the Fourth Proportional to 128.69, 193.13 and 77.39

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Solution

The fourth proportional to 128.69, 193.13 and 77.39 is: 116.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.69 : 193.13 = 77.39 : x
  2. Step 2: Convert to fraction form
    128.69/193.13 = 77.39/x
  3. Step 3: Cross multiply
    128.69x = 193.13 × 77.39
  4. Step 4: Simplify right side
    128.69x = 14,944.98
  5. Step 5: Solve for x
    x = 14,944.98/128.69
  6. Step 6: Final answer
    x = 116.14

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.