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Finding the Fourth Proportional to 721.42, 1,081.94 and 259.18

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Solution

The fourth proportional to 721.42, 1,081.94 and 259.18 is: 388.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.42 : 1,081.94 = 259.18 : x
  2. Step 2: Convert to fraction form
    721.42/1,081.94 = 259.18/x
  3. Step 3: Cross multiply
    721.42x = 1,081.94 × 259.18
  4. Step 4: Simplify right side
    721.42x = 280,417.21
  5. Step 5: Solve for x
    x = 280,417.21/721.42
  6. Step 6: Final answer
    x = 388.70

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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.