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Finding the Fourth Proportional to 428.66, 641.79 and 324.21

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Solution

The fourth proportional to 428.66, 641.79 and 324.21 is: 485.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.66 : 641.79 = 324.21 : x
  2. Step 2: Convert to fraction form
    428.66/641.79 = 324.21/x
  3. Step 3: Cross multiply
    428.66x = 641.79 × 324.21
  4. Step 4: Simplify right side
    428.66x = 208,077.14
  5. Step 5: Solve for x
    x = 208,077.14/428.66
  6. Step 6: Final answer
    x = 485.41

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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.