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Finding the Fourth Proportional to 285.89, 428.84 and 80.47

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Solution

The fourth proportional to 285.89, 428.84 and 80.47 is: 120.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.89 : 428.84 = 80.47 : x
  2. Step 2: Convert to fraction form
    285.89/428.84 = 80.47/x
  3. Step 3: Cross multiply
    285.89x = 428.84 × 80.47
  4. Step 4: Simplify right side
    285.89x = 34,507.88
  5. Step 5: Solve for x
    x = 34,507.88/285.89
  6. Step 6: Final answer
    x = 120.70

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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.