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Finding the Fourth Proportional to 420.36, 629.32 and 257.56

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Solution

The fourth proportional to 420.36, 629.32 and 257.56 is: 385.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.36 : 629.32 = 257.56 : x
  2. Step 2: Convert to fraction form
    420.36/629.32 = 257.56/x
  3. Step 3: Cross multiply
    420.36x = 629.32 × 257.56
  4. Step 4: Simplify right side
    420.36x = 162,087.66
  5. Step 5: Solve for x
    x = 162,087.66/420.36
  6. Step 6: Final answer
    x = 385.59

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.