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Finding the Fourth Proportional to 285.42, 428.34 and 208.61

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Solution

The fourth proportional to 285.42, 428.34 and 208.61 is: 313.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.42 : 428.34 = 208.61 : x
  2. Step 2: Convert to fraction form
    285.42/428.34 = 208.61/x
  3. Step 3: Cross multiply
    285.42x = 428.34 × 208.61
  4. Step 4: Simplify right side
    285.42x = 89,353.87
  5. Step 5: Solve for x
    x = 89,353.87/285.42
  6. Step 6: Final answer
    x = 313.06

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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.