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Finding the Fourth Proportional to 285.79, 428.59 and 80.30

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Solution

The fourth proportional to 285.79, 428.59 and 80.30 is: 120.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.79 : 428.59 = 80.30 : x
  2. Step 2: Convert to fraction form
    285.79/428.59 = 80.30/x
  3. Step 3: Cross multiply
    285.79x = 428.59 × 80.30
  4. Step 4: Simplify right side
    285.79x = 34,415.38
  5. Step 5: Solve for x
    x = 34,415.38/285.79
  6. Step 6: Final answer
    x = 120.42

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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.