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Finding the Fourth Proportional to 788.55, 1,087.91 and 639.11

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Solution

The fourth proportional to 788.55, 1,087.91 and 639.11 is: 881.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    788.55 : 1,087.91 = 639.11 : x
  2. Step 2: Convert to fraction form
    788.55/1,087.91 = 639.11/x
  3. Step 3: Cross multiply
    788.55x = 1,087.91 × 639.11
  4. Step 4: Simplify right side
    788.55x = 695,285.53
  5. Step 5: Solve for x
    x = 695,285.53/788.55
  6. Step 6: Final answer
    x = 881.73

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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.