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Finding the Fourth Proportional to 639.74, 956.94 and 551.78

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Solution

The fourth proportional to 639.74, 956.94 and 551.78 is: 825.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.74 : 956.94 = 551.78 : x
  2. Step 2: Convert to fraction form
    639.74/956.94 = 551.78/x
  3. Step 3: Cross multiply
    639.74x = 956.94 × 551.78
  4. Step 4: Simplify right side
    639.74x = 528,020.35
  5. Step 5: Solve for x
    x = 528,020.35/639.74
  6. Step 6: Final answer
    x = 825.37

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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.