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Finding the Fourth Proportional to 720.89, 1,081.28 and 411.77

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Solution

The fourth proportional to 720.89, 1,081.28 and 411.77 is: 617.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.89 : 1,081.28 = 411.77 : x
  2. Step 2: Convert to fraction form
    720.89/1,081.28 = 411.77/x
  3. Step 3: Cross multiply
    720.89x = 1,081.28 × 411.77
  4. Step 4: Simplify right side
    720.89x = 445,233.90
  5. Step 5: Solve for x
    x = 445,233.90/720.89
  6. Step 6: Final answer
    x = 617.62

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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.