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Finding the Fourth Proportional to 787.72, 1,087 and 438.42

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Solution

The fourth proportional to 787.72, 1,087 and 438.42 is: 604.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.72 : 1,087 = 438.42 : x
  2. Step 2: Convert to fraction form
    787.72/1,087 = 438.42/x
  3. Step 3: Cross multiply
    787.72x = 1,087 × 438.42
  4. Step 4: Simplify right side
    787.72x = 476,562.54
  5. Step 5: Solve for x
    x = 476,562.54/787.72
  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.