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Finding the Fourth Proportional to 285.90, 428.54 and 139.44

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Solution

The fourth proportional to 285.90, 428.54 and 139.44 is: 209.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.90 : 428.54 = 139.44 : x
  2. Step 2: Convert to fraction form
    285.90/428.54 = 139.44/x
  3. Step 3: Cross multiply
    285.90x = 428.54 × 139.44
  4. Step 4: Simplify right side
    285.90x = 59,755.62
  5. Step 5: Solve for x
    x = 59,755.62/285.90
  6. Step 6: Final answer
    x = 209.01

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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.