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Finding the Fourth Proportional to 1,081.09, 1,620.93 and 387.40

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Solution

The fourth proportional to 1,081.09, 1,620.93 and 387.40 is: 580.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,081.09 : 1,620.93 = 387.40 : x
  2. Step 2: Convert to fraction form
    1,081.09/1,620.93 = 387.40/x
  3. Step 3: Cross multiply
    1,081.09x = 1,620.93 × 387.40
  4. Step 4: Simplify right side
    1,081.09x = 627,948.28
  5. Step 5: Solve for x
    x = 627,948.28/1,081.09
  6. Step 6: Final answer
    x = 580.85

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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.