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Finding the Fourth Proportional to 1,378.94, 1,903 and 789.66

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Solution

The fourth proportional to 1,378.94, 1,903 and 789.66 is: 1,089.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.94 : 1,903 = 789.66 : x
  2. Step 2: Convert to fraction form
    1,378.94/1,903 = 789.66/x
  3. Step 3: Cross multiply
    1,378.94x = 1,903 × 789.66
  4. Step 4: Simplify right side
    1,378.94x = 1,502,722.98
  5. Step 5: Solve for x
    x = 1,502,722.98/1,378.94
  6. Step 6: Final answer
    x = 1,089.77

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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.