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Finding the Fourth Proportional to 787.40, 1,180.78 and 422.12

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Solution

The fourth proportional to 787.40, 1,180.78 and 422.12 is: 633.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.40 : 1,180.78 = 422.12 : x
  2. Step 2: Convert to fraction form
    787.40/1,180.78 = 422.12/x
  3. Step 3: Cross multiply
    787.40x = 1,180.78 × 422.12
  4. Step 4: Simplify right side
    787.40x = 498,432.75
  5. Step 5: Solve for x
    x = 498,432.75/787.40
  6. Step 6: Final answer
    x = 633.01

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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.