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Finding the Fourth Proportional to 428.19, 643.82 and 394.36

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Solution

The fourth proportional to 428.19, 643.82 and 394.36 is: 592.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.19 : 643.82 = 394.36 : x
  2. Step 2: Convert to fraction form
    428.19/643.82 = 394.36/x
  3. Step 3: Cross multiply
    428.19x = 643.82 × 394.36
  4. Step 4: Simplify right side
    428.19x = 253,896.54
  5. Step 5: Solve for x
    x = 253,896.54/428.19
  6. Step 6: Final answer
    x = 592.95

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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.