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Finding the Fourth Proportional to 422.30, 629.80 and 385.86

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Solution

The fourth proportional to 422.30, 629.80 and 385.86 is: 575.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    422.30 : 629.80 = 385.86 : x
  2. Step 2: Convert to fraction form
    422.30/629.80 = 385.86/x
  3. Step 3: Cross multiply
    422.30x = 629.80 × 385.86
  4. Step 4: Simplify right side
    422.30x = 243,014.63
  5. Step 5: Solve for x
    x = 243,014.63/422.30
  6. Step 6: Final answer
    x = 575.45

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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.