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Finding the Fourth Proportional to 208.11, 312.21 and 71.15

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Solution

The fourth proportional to 208.11, 312.21 and 71.15 is: 106.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.11 : 312.21 = 71.15 : x
  2. Step 2: Convert to fraction form
    208.11/312.21 = 71.15/x
  3. Step 3: Cross multiply
    208.11x = 312.21 × 71.15
  4. Step 4: Simplify right side
    208.11x = 22,213.74
  5. Step 5: Solve for x
    x = 22,213.74/208.11
  6. Step 6: Final answer
    x = 106.74

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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.