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Finding the Fourth Proportional to 419.91, 629.79 and 142.28

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Solution

The fourth proportional to 419.91, 629.79 and 142.28 is: 213.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    419.91 : 629.79 = 142.28 : x
  2. Step 2: Convert to fraction form
    419.91/629.79 = 142.28/x
  3. Step 3: Cross multiply
    419.91x = 629.79 × 142.28
  4. Step 4: Simplify right side
    419.91x = 89,603.37
  5. Step 5: Solve for x
    x = 89,603.37/419.91
  6. Step 6: Final answer
    x = 213.39

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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.