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Finding the Fourth Proportional to 420.32, 629.78 and 214.60

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Solution

The fourth proportional to 420.32, 629.78 and 214.60 is: 321.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.32 : 629.78 = 214.60 : x
  2. Step 2: Convert to fraction form
    420.32/629.78 = 214.60/x
  3. Step 3: Cross multiply
    420.32x = 629.78 × 214.60
  4. Step 4: Simplify right side
    420.32x = 135,150.79
  5. Step 5: Solve for x
    x = 135,150.79/420.32
  6. Step 6: Final answer
    x = 321.54

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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.