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Finding the Fourth Proportional to 428.91, 643.36 and 104.27

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Solution

The fourth proportional to 428.91, 643.36 and 104.27 is: 156.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.91 : 643.36 = 104.27 : x
  2. Step 2: Convert to fraction form
    428.91/643.36 = 104.27/x
  3. Step 3: Cross multiply
    428.91x = 643.36 × 104.27
  4. Step 4: Simplify right side
    428.91x = 67,083.15
  5. Step 5: Solve for x
    x = 67,083.15/428.91
  6. Step 6: Final answer
    x = 156.40

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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.