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Finding the Fourth Proportional to 129.78, 193.73 and 109.31

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Solution

The fourth proportional to 129.78, 193.73 and 109.31 is: 163.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.78 : 193.73 = 109.31 : x
  2. Step 2: Convert to fraction form
    129.78/193.73 = 109.31/x
  3. Step 3: Cross multiply
    129.78x = 193.73 × 109.31
  4. Step 4: Simplify right side
    129.78x = 21,175.11
  5. Step 5: Solve for x
    x = 21,175.11/129.78
  6. Step 6: Final answer
    x = 163.16

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.