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Finding the Fourth Proportional to 769.64, 1,061.94 and 489.78

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Solution

The fourth proportional to 769.64, 1,061.94 and 489.78 is: 675.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    769.64 : 1,061.94 = 489.78 : x
  2. Step 2: Convert to fraction form
    769.64/1,061.94 = 489.78/x
  3. Step 3: Cross multiply
    769.64x = 1,061.94 × 489.78
  4. Step 4: Simplify right side
    769.64x = 520,109.21
  5. Step 5: Solve for x
    x = 520,109.21/769.64
  6. Step 6: Final answer
    x = 675.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.