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Finding the Fourth Proportional to 1,381.72, 2,072.39 and 407.92

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Solution

The fourth proportional to 1,381.72, 2,072.39 and 407.92 is: 611.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,381.72 : 2,072.39 = 407.92 : x
  2. Step 2: Convert to fraction form
    1,381.72/2,072.39 = 407.92/x
  3. Step 3: Cross multiply
    1,381.72x = 2,072.39 × 407.92
  4. Step 4: Simplify right side
    1,381.72x = 845,369.33
  5. Step 5: Solve for x
    x = 845,369.33/1,381.72
  6. Step 6: Final answer
    x = 611.82

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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.