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Finding the Fourth Proportional to 208.09, 312.05 and 86.27

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Solution

The fourth proportional to 208.09, 312.05 and 86.27 is: 129.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.09 : 312.05 = 86.27 : x
  2. Step 2: Convert to fraction form
    208.09/312.05 = 86.27/x
  3. Step 3: Cross multiply
    208.09x = 312.05 × 86.27
  4. Step 4: Simplify right side
    208.09x = 26,920.12
  5. Step 5: Solve for x
    x = 26,920.12/208.09
  6. Step 6: Final answer
    x = 129.37

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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.