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Finding the Fourth Proportional to 285.57, 428.09 and 139.24

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Solution

The fourth proportional to 285.57, 428.09 and 139.24 is: 208.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.57 : 428.09 = 139.24 : x
  2. Step 2: Convert to fraction form
    285.57/428.09 = 139.24/x
  3. Step 3: Cross multiply
    285.57x = 428.09 × 139.24
  4. Step 4: Simplify right side
    285.57x = 59,605.11
  5. Step 5: Solve for x
    x = 59,605.11/285.57
  6. Step 6: Final answer
    x = 208.73

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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.