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Finding the Fourth Proportional to 268.78, 403.26 and 86.20

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Solution

The fourth proportional to 268.78, 403.26 and 86.20 is: 129.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    268.78 : 403.26 = 86.20 : x
  2. Step 2: Convert to fraction form
    268.78/403.26 = 86.20/x
  3. Step 3: Cross multiply
    268.78x = 403.26 × 86.20
  4. Step 4: Simplify right side
    268.78x = 34,761.01
  5. Step 5: Solve for x
    x = 34,761.01/268.78
  6. Step 6: Final answer
    x = 129.33

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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.