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Finding the Fourth Proportional to 426.32, 639.45 and 217.89

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Solution

The fourth proportional to 426.32, 639.45 and 217.89 is: 326.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.32 : 639.45 = 217.89 : x
  2. Step 2: Convert to fraction form
    426.32/639.45 = 217.89/x
  3. Step 3: Cross multiply
    426.32x = 639.45 × 217.89
  4. Step 4: Simplify right side
    426.32x = 139,329.76
  5. Step 5: Solve for x
    x = 139,329.76/426.32
  6. Step 6: Final answer
    x = 326.82

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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.