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Finding the Fourth Proportional to 787.60, 1,086.92 and 438.40

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Solution

The fourth proportional to 787.60, 1,086.92 and 438.40 is: 605.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.60 : 1,086.92 = 438.40 : x
  2. Step 2: Convert to fraction form
    787.60/1,086.92 = 438.40/x
  3. Step 3: Cross multiply
    787.60x = 1,086.92 × 438.40
  4. Step 4: Simplify right side
    787.60x = 476,505.73
  5. Step 5: Solve for x
    x = 476,505.73/787.60
  6. Step 6: Final answer
    x = 605.01

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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.