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Finding the Fourth Proportional to 428.24, 642.96 and 405.83

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Solution

The fourth proportional to 428.24, 642.96 and 405.83 is: 609.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.24 : 642.96 = 405.83 : x
  2. Step 2: Convert to fraction form
    428.24/642.96 = 405.83/x
  3. Step 3: Cross multiply
    428.24x = 642.96 × 405.83
  4. Step 4: Simplify right side
    428.24x = 260,932.46
  5. Step 5: Solve for x
    x = 260,932.46/428.24
  6. Step 6: Final answer
    x = 609.31

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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.