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Finding the Fourth Proportional to 680.78, 1,020.87 and 193.72

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Solution

The fourth proportional to 680.78, 1,020.87 and 193.72 is: 290.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.78 : 1,020.87 = 193.72 : x
  2. Step 2: Convert to fraction form
    680.78/1,020.87 = 193.72/x
  3. Step 3: Cross multiply
    680.78x = 1,020.87 × 193.72
  4. Step 4: Simplify right side
    680.78x = 197,758.61
  5. Step 5: Solve for x
    x = 197,758.61/680.78
  6. Step 6: Final answer
    x = 290.49

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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.