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Finding the Fourth Proportional to 419.78, 629.67 and 127.28

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Solution

The fourth proportional to 419.78, 629.67 and 127.28 is: 190.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    419.78 : 629.67 = 127.28 : x
  2. Step 2: Convert to fraction form
    419.78/629.67 = 127.28/x
  3. Step 3: Cross multiply
    419.78x = 629.67 × 127.28
  4. Step 4: Simplify right side
    419.78x = 80,144.40
  5. Step 5: Solve for x
    x = 80,144.40/419.78
  6. Step 6: Final answer
    x = 190.92

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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.