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Finding the Fourth Proportional to 420.32, 629.64 and 214.88

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Solution

The fourth proportional to 420.32, 629.64 and 214.88 is: 321.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.32 : 629.64 = 214.88 : x
  2. Step 2: Convert to fraction form
    420.32/629.64 = 214.88/x
  3. Step 3: Cross multiply
    420.32x = 629.64 × 214.88
  4. Step 4: Simplify right side
    420.32x = 135,297.04
  5. Step 5: Solve for x
    x = 135,297.04/420.32
  6. Step 6: Final answer
    x = 321.89

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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.