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Finding the Fourth Proportional to 1,379.78, 2,069.13 and 721.46

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Solution

The fourth proportional to 1,379.78, 2,069.13 and 721.46 is: 1,081.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,379.78 : 2,069.13 = 721.46 : x
  2. Step 2: Convert to fraction form
    1,379.78/2,069.13 = 721.46/x
  3. Step 3: Cross multiply
    1,379.78x = 2,069.13 × 721.46
  4. Step 4: Simplify right side
    1,379.78x = 1,492,794.53
  5. Step 5: Solve for x
    x = 1,492,794.53/1,379.78
  6. Step 6: Final answer
    x = 1,081.91

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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.