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Finding the Fourth Proportional to 426.26, 639.70 and 387.99

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Solution

The fourth proportional to 426.26, 639.70 and 387.99 is: 582.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.26 : 639.70 = 387.99 : x
  2. Step 2: Convert to fraction form
    426.26/639.70 = 387.99/x
  3. Step 3: Cross multiply
    426.26x = 639.70 × 387.99
  4. Step 4: Simplify right side
    426.26x = 248,196.23
  5. Step 5: Solve for x
    x = 248,196.23/426.26
  6. Step 6: Final answer
    x = 582.26

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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.