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Finding the Fourth Proportional to 426.84, 640.32 and 138.28

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Solution

The fourth proportional to 426.84, 640.32 and 138.28 is: 207.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.84 : 640.32 = 138.28 : x
  2. Step 2: Convert to fraction form
    426.84/640.32 = 138.28/x
  3. Step 3: Cross multiply
    426.84x = 640.32 × 138.28
  4. Step 4: Simplify right side
    426.84x = 88,543.45
  5. Step 5: Solve for x
    x = 88,543.45/426.84
  6. Step 6: Final answer
    x = 207.44

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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.