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Finding the Fourth Proportional to 428.60, 643.29 and 223.31

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Solution

The fourth proportional to 428.60, 643.29 and 223.31 is: 335.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.60 : 643.29 = 223.31 : x
  2. Step 2: Convert to fraction form
    428.60/643.29 = 223.31/x
  3. Step 3: Cross multiply
    428.60x = 643.29 × 223.31
  4. Step 4: Simplify right side
    428.60x = 143,653.09
  5. Step 5: Solve for x
    x = 143,653.09/428.60
  6. Step 6: Final answer
    x = 335.17

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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.