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Finding the Fourth Proportional to 426.30, 643.07 and 408.30

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Solution

The fourth proportional to 426.30, 643.07 and 408.30 is: 615.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.30 : 643.07 = 408.30 : x
  2. Step 2: Convert to fraction form
    426.30/643.07 = 408.30/x
  3. Step 3: Cross multiply
    426.30x = 643.07 × 408.30
  4. Step 4: Simplify right side
    426.30x = 262,563.44
  5. Step 5: Solve for x
    x = 262,563.44/426.30
  6. Step 6: Final answer
    x = 615.91

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.