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Finding the Fourth Proportional to 431.21, 642.33 and 408.12

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Solution

The fourth proportional to 431.21, 642.33 and 408.12 is: 607.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.21 : 642.33 = 408.12 : x
  2. Step 2: Convert to fraction form
    431.21/642.33 = 408.12/x
  3. Step 3: Cross multiply
    431.21x = 642.33 × 408.12
  4. Step 4: Simplify right side
    431.21x = 262,147.72
  5. Step 5: Solve for x
    x = 262,147.72/431.21
  6. Step 6: Final answer
    x = 607.94

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.