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Finding the Fourth Proportional to 428.87, 643.50 and 223.40

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Solution

The fourth proportional to 428.87, 643.50 and 223.40 is: 335.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.87 : 643.50 = 223.40 : x
  2. Step 2: Convert to fraction form
    428.87/643.50 = 223.40/x
  3. Step 3: Cross multiply
    428.87x = 643.50 × 223.40
  4. Step 4: Simplify right side
    428.87x = 143,754.68
  5. Step 5: Solve for x
    x = 143,754.68/428.87
  6. Step 6: Final answer
    x = 335.20

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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.