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Finding the Fourth Proportional to 667.90, 1,000.74 and 408.20

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Solution

The fourth proportional to 667.90, 1,000.74 and 408.20 is: 611.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    667.90 : 1,000.74 = 408.20 : x
  2. Step 2: Convert to fraction form
    667.90/1,000.74 = 408.20/x
  3. Step 3: Cross multiply
    667.90x = 1,000.74 × 408.20
  4. Step 4: Simplify right side
    667.90x = 408,502.07
  5. Step 5: Solve for x
    x = 408,502.07/667.90
  6. Step 6: Final answer
    x = 611.62

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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.