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Finding the Fourth Proportional to 721.01, 1,081.57 and 258.79

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Solution

The fourth proportional to 721.01, 1,081.57 and 258.79 is: 388.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.01 : 1,081.57 = 258.79 : x
  2. Step 2: Convert to fraction form
    721.01/1,081.57 = 258.79/x
  3. Step 3: Cross multiply
    721.01x = 1,081.57 × 258.79
  4. Step 4: Simplify right side
    721.01x = 279,900.98
  5. Step 5: Solve for x
    x = 279,900.98/721.01
  6. Step 6: Final answer
    x = 388.21

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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.