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Finding the Fourth Proportional to 285.42, 428.31 and 208.38

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Solution

The fourth proportional to 285.42, 428.31 and 208.38 is: 312.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.42 : 428.31 = 208.38 : x
  2. Step 2: Convert to fraction form
    285.42/428.31 = 208.38/x
  3. Step 3: Cross multiply
    285.42x = 428.31 × 208.38
  4. Step 4: Simplify right side
    285.42x = 89,251.24
  5. Step 5: Solve for x
    x = 89,251.24/285.42
  6. Step 6: Final answer
    x = 312.70

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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.