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Finding the Fourth Proportional to 721.19, 1,081.59 and 258.91

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Solution

The fourth proportional to 721.19, 1,081.59 and 258.91 is: 388.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.19 : 1,081.59 = 258.91 : x
  2. Step 2: Convert to fraction form
    721.19/1,081.59 = 258.91/x
  3. Step 3: Cross multiply
    721.19x = 1,081.59 × 258.91
  4. Step 4: Simplify right side
    721.19x = 280,034.47
  5. Step 5: Solve for x
    x = 280,034.47/721.19
  6. Step 6: Final answer
    x = 388.30

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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.