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Finding the Fourth Proportional to 680.43, 1,020.80 and 315.02

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Solution

The fourth proportional to 680.43, 1,020.80 and 315.02 is: 472.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.43 : 1,020.80 = 315.02 : x
  2. Step 2: Convert to fraction form
    680.43/1,020.80 = 315.02/x
  3. Step 3: Cross multiply
    680.43x = 1,020.80 × 315.02
  4. Step 4: Simplify right side
    680.43x = 321,575.76
  5. Step 5: Solve for x
    x = 321,575.76/680.43
  6. Step 6: Final answer
    x = 472.60

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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.