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Finding the Fourth Proportional to 426.99, 640.47 and 138.42

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Solution

The fourth proportional to 426.99, 640.47 and 138.42 is: 207.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.99 : 640.47 = 138.42 : x
  2. Step 2: Convert to fraction form
    426.99/640.47 = 138.42/x
  3. Step 3: Cross multiply
    426.99x = 640.47 × 138.42
  4. Step 4: Simplify right side
    426.99x = 88,653.86
  5. Step 5: Solve for x
    x = 88,653.86/426.99
  6. Step 6: Final answer
    x = 207.63

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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.