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Finding the Fourth Proportional to 680.31, 1,020.05 and 314.90

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Solution

The fourth proportional to 680.31, 1,020.05 and 314.90 is: 472.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.31 : 1,020.05 = 314.90 : x
  2. Step 2: Convert to fraction form
    680.31/1,020.05 = 314.90/x
  3. Step 3: Cross multiply
    680.31x = 1,020.05 × 314.90
  4. Step 4: Simplify right side
    680.31x = 321,207.07
  5. Step 5: Solve for x
    x = 321,207.07/680.31
  6. Step 6: Final answer
    x = 472.15

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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.