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Finding the Fourth Proportional to 422.34, 629.76 and 421.56

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Solution

The fourth proportional to 422.34, 629.76 and 421.56 is: 628.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    422.34 : 629.76 = 421.56 : x
  2. Step 2: Convert to fraction form
    422.34/629.76 = 421.56/x
  3. Step 3: Cross multiply
    422.34x = 629.76 × 421.56
  4. Step 4: Simplify right side
    422.34x = 265,481.63
  5. Step 5: Solve for x
    x = 265,481.63/422.34
  6. Step 6: Final answer
    x = 628.60

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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.