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Finding the Fourth Proportional to 787.90, 1,087.34 and 438.58

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Solution

The fourth proportional to 787.90, 1,087.34 and 438.58 is: 605.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.90 : 1,087.34 = 438.58 : x
  2. Step 2: Convert to fraction form
    787.90/1,087.34 = 438.58/x
  3. Step 3: Cross multiply
    787.90x = 1,087.34 × 438.58
  4. Step 4: Simplify right side
    787.90x = 476,885.58
  5. Step 5: Solve for x
    x = 476,885.58/787.90
  6. Step 6: Final answer
    x = 605.26

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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.