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Finding the Fourth Proportional to 721.08, 1,081.47 and 258.89

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Solution

The fourth proportional to 721.08, 1,081.47 and 258.89 is: 388.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.08 : 1,081.47 = 258.89 : x
  2. Step 2: Convert to fraction form
    721.08/1,081.47 = 258.89/x
  3. Step 3: Cross multiply
    721.08x = 1,081.47 × 258.89
  4. Step 4: Simplify right side
    721.08x = 279,977.71
  5. Step 5: Solve for x
    x = 279,977.71/721.08
  6. Step 6: Final answer
    x = 388.27

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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.