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Finding the Fourth Proportional to 428.67, 643.21 and 223.13

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Solution

The fourth proportional to 428.67, 643.21 and 223.13 is: 334.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.67 : 643.21 = 223.13 : x
  2. Step 2: Convert to fraction form
    428.67/643.21 = 223.13/x
  3. Step 3: Cross multiply
    428.67x = 643.21 × 223.13
  4. Step 4: Simplify right side
    428.67x = 143,519.45
  5. Step 5: Solve for x
    x = 143,519.45/428.67
  6. Step 6: Final answer
    x = 334.80

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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.