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Finding the Fourth Proportional to 129.16, 177.45 and 105.78

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Solution

The fourth proportional to 129.16, 177.45 and 105.78 is: 145.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.16 : 177.45 = 105.78 : x
  2. Step 2: Convert to fraction form
    129.16/177.45 = 105.78/x
  3. Step 3: Cross multiply
    129.16x = 177.45 × 105.78
  4. Step 4: Simplify right side
    129.16x = 18,770.66
  5. Step 5: Solve for x
    x = 18,770.66/129.16
  6. Step 6: Final answer
    x = 145.33

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.