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Finding the Fourth Proportional to 721.35, 1,081.55 and 409.01

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Solution

The fourth proportional to 721.35, 1,081.55 and 409.01 is: 613.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.35 : 1,081.55 = 409.01 : x
  2. Step 2: Convert to fraction form
    721.35/1,081.55 = 409.01/x
  3. Step 3: Cross multiply
    721.35x = 1,081.55 × 409.01
  4. Step 4: Simplify right side
    721.35x = 442,360.38
  5. Step 5: Solve for x
    x = 442,360.38/721.35
  6. Step 6: Final answer
    x = 613.24

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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.