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Finding the Fourth Proportional to 285.50, 428.35 and 139.29

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Solution

The fourth proportional to 285.50, 428.35 and 139.29 is: 208.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.50 : 428.35 = 139.29 : x
  2. Step 2: Convert to fraction form
    285.50/428.35 = 139.29/x
  3. Step 3: Cross multiply
    285.50x = 428.35 × 139.29
  4. Step 4: Simplify right side
    285.50x = 59,664.87
  5. Step 5: Solve for x
    x = 59,664.87/285.50
  6. Step 6: Final answer
    x = 208.98

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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.