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Finding the Fourth Proportional to 431.14, 646.53 and 138.56

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Solution

The fourth proportional to 431.14, 646.53 and 138.56 is: 207.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.14 : 646.53 = 138.56 : x
  2. Step 2: Convert to fraction form
    431.14/646.53 = 138.56/x
  3. Step 3: Cross multiply
    431.14x = 646.53 × 138.56
  4. Step 4: Simplify right side
    431.14x = 89,583.20
  5. Step 5: Solve for x
    x = 89,583.20/431.14
  6. Step 6: Final answer
    x = 207.78

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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.