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Finding the Fourth Proportional to 431.48, 647.06 and 138.97

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Solution

The fourth proportional to 431.48, 647.06 and 138.97 is: 208.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.48 : 647.06 = 138.97 : x
  2. Step 2: Convert to fraction form
    431.48/647.06 = 138.97/x
  3. Step 3: Cross multiply
    431.48x = 647.06 × 138.97
  4. Step 4: Simplify right side
    431.48x = 89,919.58
  5. Step 5: Solve for x
    x = 89,919.58/431.48
  6. Step 6: Final answer
    x = 208.40

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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.