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Finding the Fourth Proportional to 787.70, 1,181.78 and 422.21

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Solution

The fourth proportional to 787.70, 1,181.78 and 422.21 is: 633.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.70 : 1,181.78 = 422.21 : x
  2. Step 2: Convert to fraction form
    787.70/1,181.78 = 422.21/x
  3. Step 3: Cross multiply
    787.70x = 1,181.78 × 422.21
  4. Step 4: Simplify right side
    787.70x = 498,959.33
  5. Step 5: Solve for x
    x = 498,959.33/787.70
  6. Step 6: Final answer
    x = 633.44

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.