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Finding the Fourth Proportional to 426.90, 640.38 and 345.90

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Solution

The fourth proportional to 426.90, 640.38 and 345.90 is: 518.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.90 : 640.38 = 345.90 : x
  2. Step 2: Convert to fraction form
    426.90/640.38 = 345.90/x
  3. Step 3: Cross multiply
    426.90x = 640.38 × 345.90
  4. Step 4: Simplify right side
    426.90x = 221,507.44
  5. Step 5: Solve for x
    x = 221,507.44/426.90
  6. Step 6: Final answer
    x = 518.87

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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.