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Finding the Fourth Proportional to 420.24, 629.43 and 257.43

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Solution

The fourth proportional to 420.24, 629.43 and 257.43 is: 385.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.24 : 629.43 = 257.43 : x
  2. Step 2: Convert to fraction form
    420.24/629.43 = 257.43/x
  3. Step 3: Cross multiply
    420.24x = 629.43 × 257.43
  4. Step 4: Simplify right side
    420.24x = 162,034.16
  5. Step 5: Solve for x
    x = 162,034.16/420.24
  6. Step 6: Final answer
    x = 385.58

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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.