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Finding the Fourth Proportional to 431.26, 646.72 and 138.66

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Solution

The fourth proportional to 431.26, 646.72 and 138.66 is: 207.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.26 : 646.72 = 138.66 : x
  2. Step 2: Convert to fraction form
    431.26/646.72 = 138.66/x
  3. Step 3: Cross multiply
    431.26x = 646.72 × 138.66
  4. Step 4: Simplify right side
    431.26x = 89,674.20
  5. Step 5: Solve for x
    x = 89,674.20/431.26
  6. Step 6: Final answer
    x = 207.94

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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.