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Finding the Fourth Proportional to 426.17, 639 and 217.81

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Solution

The fourth proportional to 426.17, 639 and 217.81 is: 326.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.17 : 639 = 217.81 : x
  2. Step 2: Convert to fraction form
    426.17/639 = 217.81/x
  3. Step 3: Cross multiply
    426.17x = 639 × 217.81
  4. Step 4: Simplify right side
    426.17x = 139,178.99
  5. Step 5: Solve for x
    x = 139,178.99/426.17
  6. Step 6: Final answer
    x = 326.58

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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.