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Finding the Fourth Proportional to 787.71, 1,087.04 and 438.40

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Solution

The fourth proportional to 787.71, 1,087.04 and 438.40 is: 604.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.71 : 1,087.04 = 438.40 : x
  2. Step 2: Convert to fraction form
    787.71/1,087.04 = 438.40/x
  3. Step 3: Cross multiply
    787.71x = 1,087.04 × 438.40
  4. Step 4: Simplify right side
    787.71x = 476,550.71
  5. Step 5: Solve for x
    x = 476,550.71/787.71
  6. Step 6: Final answer
    x = 604.99

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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.