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Finding the Fourth Proportional to 426.54, 639.12 and 220.80

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Solution

The fourth proportional to 426.54, 639.12 and 220.80 is: 330.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.54 : 639.12 = 220.80 : x
  2. Step 2: Convert to fraction form
    426.54/639.12 = 220.80/x
  3. Step 3: Cross multiply
    426.54x = 639.12 × 220.80
  4. Step 4: Simplify right side
    426.54x = 141,117.70
  5. Step 5: Solve for x
    x = 141,117.70/426.54
  6. Step 6: Final answer
    x = 330.84

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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.