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Finding the Fourth Proportional to 787.40, 1,086.62 and 438.09

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Solution

The fourth proportional to 787.40, 1,086.62 and 438.09 is: 604.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.40 : 1,086.62 = 438.09 : x
  2. Step 2: Convert to fraction form
    787.40/1,086.62 = 438.09/x
  3. Step 3: Cross multiply
    787.40x = 1,086.62 × 438.09
  4. Step 4: Simplify right side
    787.40x = 476,036.26
  5. Step 5: Solve for x
    x = 476,036.26/787.40
  6. Step 6: Final answer
    x = 604.57

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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.