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Finding the Fourth Proportional to 431.11, 646.66 and 138.61

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Solution

The fourth proportional to 431.11, 646.66 and 138.61 is: 207.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.11 : 646.66 = 138.61 : x
  2. Step 2: Convert to fraction form
    431.11/646.66 = 138.61/x
  3. Step 3: Cross multiply
    431.11x = 646.66 × 138.61
  4. Step 4: Simplify right side
    431.11x = 89,630.31
  5. Step 5: Solve for x
    x = 89,630.31/431.11
  6. Step 6: Final answer
    x = 207.91

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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.