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Finding the Fourth Proportional to 426.53, 639.36 and 221.20

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Solution

The fourth proportional to 426.53, 639.36 and 221.20 is: 331.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.53 : 639.36 = 221.20 : x
  2. Step 2: Convert to fraction form
    426.53/639.36 = 221.20/x
  3. Step 3: Cross multiply
    426.53x = 639.36 × 221.20
  4. Step 4: Simplify right side
    426.53x = 141,424.83
  5. Step 5: Solve for x
    x = 141,424.83/426.53
  6. Step 6: Final answer
    x = 331.57

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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.