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Finding the Fourth Proportional to 685.20, 1,027.21 and 314.88

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Solution

The fourth proportional to 685.20, 1,027.21 and 314.88 is: 472.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.20 : 1,027.21 = 314.88 : x
  2. Step 2: Convert to fraction form
    685.20/1,027.21 = 314.88/x
  3. Step 3: Cross multiply
    685.20x = 1,027.21 × 314.88
  4. Step 4: Simplify right side
    685.20x = 323,441.17
  5. Step 5: Solve for x
    x = 323,441.17/685.20
  6. Step 6: Final answer
    x = 472.04

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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.