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Finding the Fourth Proportional to 419.92, 629.78 and 211.55

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Solution

The fourth proportional to 419.92, 629.78 and 211.55 is: 317.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    419.92 : 629.78 = 211.55 : x
  2. Step 2: Convert to fraction form
    419.92/629.78 = 211.55/x
  3. Step 3: Cross multiply
    419.92x = 629.78 × 211.55
  4. Step 4: Simplify right side
    419.92x = 133,225.75
  5. Step 5: Solve for x
    x = 133,225.75/419.92
  6. Step 6: Final answer
    x = 317.27

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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.