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Finding the Fourth Proportional to 769.74, 1,152.98 and 639.42

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Solution

The fourth proportional to 769.74, 1,152.98 and 639.42 is: 957.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    769.74 : 1,152.98 = 639.42 : x
  2. Step 2: Convert to fraction form
    769.74/1,152.98 = 639.42/x
  3. Step 3: Cross multiply
    769.74x = 1,152.98 × 639.42
  4. Step 4: Simplify right side
    769.74x = 737,238.47
  5. Step 5: Solve for x
    x = 737,238.47/769.74
  6. Step 6: Final answer
    x = 957.78

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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.