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Finding the Fourth Proportional to 680.64, 1,020.96 and 391.92

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Solution

The fourth proportional to 680.64, 1,020.96 and 391.92 is: 587.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.64 : 1,020.96 = 391.92 : x
  2. Step 2: Convert to fraction form
    680.64/1,020.96 = 391.92/x
  3. Step 3: Cross multiply
    680.64x = 1,020.96 × 391.92
  4. Step 4: Simplify right side
    680.64x = 400,134.64
  5. Step 5: Solve for x
    x = 400,134.64/680.64
  6. Step 6: Final answer
    x = 587.88

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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.