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Finding the Fourth Proportional to 426.66, 639.78 and 221.22

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Solution

The fourth proportional to 426.66, 639.78 and 221.22 is: 331.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.66 : 639.78 = 221.22 : x
  2. Step 2: Convert to fraction form
    426.66/639.78 = 221.22/x
  3. Step 3: Cross multiply
    426.66x = 639.78 × 221.22
  4. Step 4: Simplify right side
    426.66x = 141,532.13
  5. Step 5: Solve for x
    x = 141,532.13/426.66
  6. Step 6: Final answer
    x = 331.72

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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.