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Finding the Fourth Proportional to 668.61, 1,003.31 and 257.78

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Solution

The fourth proportional to 668.61, 1,003.31 and 257.78 is: 386.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    668.61 : 1,003.31 = 257.78 : x
  2. Step 2: Convert to fraction form
    668.61/1,003.31 = 257.78/x
  3. Step 3: Cross multiply
    668.61x = 1,003.31 × 257.78
  4. Step 4: Simplify right side
    668.61x = 258,626.95
  5. Step 5: Solve for x
    x = 258,626.95/668.61
  6. Step 6: Final answer
    x = 386.81

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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.