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Finding the Fourth Proportional to 431.41, 646.96 and 138.89

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Solution

The fourth proportional to 431.41, 646.96 and 138.89 is: 208.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.41 : 646.96 = 138.89 : x
  2. Step 2: Convert to fraction form
    431.41/646.96 = 138.89/x
  3. Step 3: Cross multiply
    431.41x = 646.96 × 138.89
  4. Step 4: Simplify right side
    431.41x = 89,858.01
  5. Step 5: Solve for x
    x = 89,858.01/431.41
  6. Step 6: Final answer
    x = 208.29

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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.