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Finding the Fourth Proportional to 285.72, 428.79 and 220.88

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Solution

The fourth proportional to 285.72, 428.79 and 220.88 is: 331.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.72 : 428.79 = 220.88 : x
  2. Step 2: Convert to fraction form
    285.72/428.79 = 220.88/x
  3. Step 3: Cross multiply
    285.72x = 428.79 × 220.88
  4. Step 4: Simplify right side
    285.72x = 94,711.14
  5. Step 5: Solve for x
    x = 94,711.14/285.72
  6. Step 6: Final answer
    x = 331.48

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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.