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Finding the Fourth Proportional to 420.69, 629.87 and 214.82

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Solution

The fourth proportional to 420.69, 629.87 and 214.82 is: 321.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.69 : 629.87 = 214.82 : x
  2. Step 2: Convert to fraction form
    420.69/629.87 = 214.82/x
  3. Step 3: Cross multiply
    420.69x = 629.87 × 214.82
  4. Step 4: Simplify right side
    420.69x = 135,308.67
  5. Step 5: Solve for x
    x = 135,308.67/420.69
  6. Step 6: Final answer
    x = 321.64

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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.