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Finding the Fourth Proportional to 680.80, 1,020.36 and 315.48

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Solution

The fourth proportional to 680.80, 1,020.36 and 315.48 is: 472.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.80 : 1,020.36 = 315.48 : x
  2. Step 2: Convert to fraction form
    680.80/1,020.36 = 315.48/x
  3. Step 3: Cross multiply
    680.80x = 1,020.36 × 315.48
  4. Step 4: Simplify right side
    680.80x = 321,903.17
  5. Step 5: Solve for x
    x = 321,903.17/680.80
  6. Step 6: Final answer
    x = 472.83

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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.