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Finding the Fourth Proportional to 208, 312.04 and 86.28

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Solution

The fourth proportional to 208, 312.04 and 86.28 is: 129.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    208 : 312.04 = 86.28 : x
  2. Step 2: Convert to fraction form
    208/312.04 = 86.28/x
  3. Step 3: Cross multiply
    208x = 312.04 × 86.28
  4. Step 4: Simplify right side
    208x = 26,922.81
  5. Step 5: Solve for x
    x = 26,922.81/208
  6. Step 6: Final answer
    x = 129.44

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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.