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Finding the Fourth Proportional to 207.78, 286.76 and 129.15

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Solution

The fourth proportional to 207.78, 286.76 and 129.15 is: 178.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    207.78 : 286.76 = 129.15 : x
  2. Step 2: Convert to fraction form
    207.78/286.76 = 129.15/x
  3. Step 3: Cross multiply
    207.78x = 286.76 × 129.15
  4. Step 4: Simplify right side
    207.78x = 37,035.05
  5. Step 5: Solve for x
    x = 37,035.05/207.78
  6. Step 6: Final answer
    x = 178.24

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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.