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Finding the Fourth Proportional to 431.97, 647.64 and 139.37

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Solution

The fourth proportional to 431.97, 647.64 and 139.37 is: 208.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.97 : 647.64 = 139.37 : x
  2. Step 2: Convert to fraction form
    431.97/647.64 = 139.37/x
  3. Step 3: Cross multiply
    431.97x = 647.64 × 139.37
  4. Step 4: Simplify right side
    431.97x = 90,258.35
  5. Step 5: Solve for x
    x = 90,258.35/431.97
  6. Step 6: Final answer
    x = 208.95

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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.