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Finding the Fourth Proportional to 426.37, 639.75 and 220.90

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Solution

The fourth proportional to 426.37, 639.75 and 220.90 is: 331.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.37 : 639.75 = 220.90 : x
  2. Step 2: Convert to fraction form
    426.37/639.75 = 220.90/x
  3. Step 3: Cross multiply
    426.37x = 639.75 × 220.90
  4. Step 4: Simplify right side
    426.37x = 141,317.58
  5. Step 5: Solve for x
    x = 141,317.58/426.37
  6. Step 6: Final answer
    x = 331.45

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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.