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Finding the Fourth Proportional to 428.71, 643.20 and 223.43

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Solution

The fourth proportional to 428.71, 643.20 and 223.43 is: 335.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.71 : 643.20 = 223.43 : x
  2. Step 2: Convert to fraction form
    428.71/643.20 = 223.43/x
  3. Step 3: Cross multiply
    428.71x = 643.20 × 223.43
  4. Step 4: Simplify right side
    428.71x = 143,710.18
  5. Step 5: Solve for x
    x = 143,710.18/428.71
  6. Step 6: Final answer
    x = 335.22

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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.