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Finding the Fourth Proportional to 439.19, 654.91 and 428.70

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Solution

The fourth proportional to 439.19, 654.91 and 428.70 is: 639.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    439.19 : 654.91 = 428.70 : x
  2. Step 2: Convert to fraction form
    439.19/654.91 = 428.70/x
  3. Step 3: Cross multiply
    439.19x = 654.91 × 428.70
  4. Step 4: Simplify right side
    439.19x = 280,759.92
  5. Step 5: Solve for x
    x = 280,759.92/439.19
  6. Step 6: Final answer
    x = 639.27

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.