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Finding the Fourth Proportional to 428.81, 643.55 and 223.55

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Solution

The fourth proportional to 428.81, 643.55 and 223.55 is: 335.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.81 : 643.55 = 223.55 : x
  2. Step 2: Convert to fraction form
    428.81/643.55 = 223.55/x
  3. Step 3: Cross multiply
    428.81x = 643.55 × 223.55
  4. Step 4: Simplify right side
    428.81x = 143,861.27
  5. Step 5: Solve for x
    x = 143,861.27/428.81
  6. Step 6: Final answer
    x = 335.49

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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.