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Finding the Fourth Proportional to 787.76, 1,087.09 and 438.50

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Solution

The fourth proportional to 787.76, 1,087.09 and 438.50 is: 605.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.76 : 1,087.09 = 438.50 : x
  2. Step 2: Convert to fraction form
    787.76/1,087.09 = 438.50/x
  3. Step 3: Cross multiply
    787.76x = 1,087.09 × 438.50
  4. Step 4: Simplify right side
    787.76x = 476,688.97
  5. Step 5: Solve for x
    x = 476,688.97/787.76
  6. Step 6: Final answer
    x = 605.12

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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.