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Finding the Fourth Proportional to 789.94, 1,185.92 and 420.18

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Solution

The fourth proportional to 789.94, 1,185.92 and 420.18 is: 630.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    789.94 : 1,185.92 = 420.18 : x
  2. Step 2: Convert to fraction form
    789.94/1,185.92 = 420.18/x
  3. Step 3: Cross multiply
    789.94x = 1,185.92 × 420.18
  4. Step 4: Simplify right side
    789.94x = 498,299.87
  5. Step 5: Solve for x
    x = 498,299.87/789.94
  6. Step 6: Final answer
    x = 630.81

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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.