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Finding the Fourth Proportional to 428.78, 643.32 and 223.24

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Solution

The fourth proportional to 428.78, 643.32 and 223.24 is: 334.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.78 : 643.32 = 223.24 : x
  2. Step 2: Convert to fraction form
    428.78/643.32 = 223.24/x
  3. Step 3: Cross multiply
    428.78x = 643.32 × 223.24
  4. Step 4: Simplify right side
    428.78x = 143,614.76
  5. Step 5: Solve for x
    x = 143,614.76/428.78
  6. Step 6: Final answer
    x = 334.94

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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.