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Finding the Fourth Proportional to 720.40, 1,081.32 and 395.92

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Solution

The fourth proportional to 720.40, 1,081.32 and 395.92 is: 594.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.40 : 1,081.32 = 395.92 : x
  2. Step 2: Convert to fraction form
    720.40/1,081.32 = 395.92/x
  3. Step 3: Cross multiply
    720.40x = 1,081.32 × 395.92
  4. Step 4: Simplify right side
    720.40x = 428,116.21
  5. Step 5: Solve for x
    x = 428,116.21/720.40
  6. Step 6: Final answer
    x = 594.28

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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.