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Finding the Fourth Proportional to 1,381.92, 2,072.60 and 407.78

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Solution

The fourth proportional to 1,381.92, 2,072.60 and 407.78 is: 611.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,381.92 : 2,072.60 = 407.78 : x
  2. Step 2: Convert to fraction form
    1,381.92/2,072.60 = 407.78/x
  3. Step 3: Cross multiply
    1,381.92x = 2,072.60 × 407.78
  4. Step 4: Simplify right side
    1,381.92x = 845,164.83
  5. Step 5: Solve for x
    x = 845,164.83/1,381.92
  6. Step 6: Final answer
    x = 611.59

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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.