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Finding the Fourth Proportional to 422.40, 629.95 and 386.97

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Solution

The fourth proportional to 422.40, 629.95 and 386.97 is: 577.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    422.40 : 629.95 = 386.97 : x
  2. Step 2: Convert to fraction form
    422.40/629.95 = 386.97/x
  3. Step 3: Cross multiply
    422.40x = 629.95 × 386.97
  4. Step 4: Simplify right side
    422.40x = 243,771.75
  5. Step 5: Solve for x
    x = 243,771.75/422.40
  6. Step 6: Final answer
    x = 577.11

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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.