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Finding the Fourth Proportional to 428.98, 643.20 and 223.65

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Solution

The fourth proportional to 428.98, 643.20 and 223.65 is: 335.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.98 : 643.20 = 223.65 : x
  2. Step 2: Convert to fraction form
    428.98/643.20 = 223.65/x
  3. Step 3: Cross multiply
    428.98x = 643.20 × 223.65
  4. Step 4: Simplify right side
    428.98x = 143,851.68
  5. Step 5: Solve for x
    x = 143,851.68/428.98
  6. Step 6: Final answer
    x = 335.33

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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.