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Finding the Fourth Proportional to 420.20, 629.72 and 311.64

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Solution

The fourth proportional to 420.20, 629.72 and 311.64 is: 467.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.20 : 629.72 = 311.64 : x
  2. Step 2: Convert to fraction form
    420.20/629.72 = 311.64/x
  3. Step 3: Cross multiply
    420.20x = 629.72 × 311.64
  4. Step 4: Simplify right side
    420.20x = 196,245.94
  5. Step 5: Solve for x
    x = 196,245.94/420.20
  6. Step 6: Final answer
    x = 467.03

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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.