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Finding the Fourth Proportional to 788.66, 1,087.82 and 639.33

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Solution

The fourth proportional to 788.66, 1,087.82 and 639.33 is: 881.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    788.66 : 1,087.82 = 639.33 : x
  2. Step 2: Convert to fraction form
    788.66/1,087.82 = 639.33/x
  3. Step 3: Cross multiply
    788.66x = 1,087.82 × 639.33
  4. Step 4: Simplify right side
    788.66x = 695,475.96
  5. Step 5: Solve for x
    x = 695,475.96/788.66
  6. Step 6: Final answer
    x = 881.85

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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.