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Finding the Fourth Proportional to 426.94, 640.53 and 138.40

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Solution

The fourth proportional to 426.94, 640.53 and 138.40 is: 207.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.94 : 640.53 = 138.40 : x
  2. Step 2: Convert to fraction form
    426.94/640.53 = 138.40/x
  3. Step 3: Cross multiply
    426.94x = 640.53 × 138.40
  4. Step 4: Simplify right side
    426.94x = 88,649.35
  5. Step 5: Solve for x
    x = 88,649.35/426.94
  6. Step 6: Final answer
    x = 207.64

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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.