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Finding the Fourth Proportional to 422.67, 638.64 and 420.24

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Solution

The fourth proportional to 422.67, 638.64 and 420.24 is: 634.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    422.67 : 638.64 = 420.24 : x
  2. Step 2: Convert to fraction form
    422.67/638.64 = 420.24/x
  3. Step 3: Cross multiply
    422.67x = 638.64 × 420.24
  4. Step 4: Simplify right side
    422.67x = 268,382.07
  5. Step 5: Solve for x
    x = 268,382.07/422.67
  6. Step 6: Final answer
    x = 634.97

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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.