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Finding the Fourth Proportional to 721.39, 1,081.41 and 258.92

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Solution

The fourth proportional to 721.39, 1,081.41 and 258.92 is: 388.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.39 : 1,081.41 = 258.92 : x
  2. Step 2: Convert to fraction form
    721.39/1,081.41 = 258.92/x
  3. Step 3: Cross multiply
    721.39x = 1,081.41 × 258.92
  4. Step 4: Simplify right side
    721.39x = 279,994.82
  5. Step 5: Solve for x
    x = 279,994.82/721.39
  6. Step 6: Final answer
    x = 388.13

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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.