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Finding the Fourth Proportional to 859.61, 1,185.91 and 639.09

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Solution

The fourth proportional to 859.61, 1,185.91 and 639.09 is: 881.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.61 : 1,185.91 = 639.09 : x
  2. Step 2: Convert to fraction form
    859.61/1,185.91 = 639.09/x
  3. Step 3: Cross multiply
    859.61x = 1,185.91 × 639.09
  4. Step 4: Simplify right side
    859.61x = 757,901.62
  5. Step 5: Solve for x
    x = 757,901.62/859.61
  6. Step 6: Final answer
    x = 881.68

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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.