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Finding the Fourth Proportional to 426.95, 639.88 and 221.12

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Solution

The fourth proportional to 426.95, 639.88 and 221.12 is: 331.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.95 : 639.88 = 221.12 : x
  2. Step 2: Convert to fraction form
    426.95/639.88 = 221.12/x
  3. Step 3: Cross multiply
    426.95x = 639.88 × 221.12
  4. Step 4: Simplify right side
    426.95x = 141,490.27
  5. Step 5: Solve for x
    x = 141,490.27/426.95
  6. Step 6: Final answer
    x = 331.40

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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.