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Finding the Fourth Proportional to 428.96, 643.35 and 120.83

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Solution

The fourth proportional to 428.96, 643.35 and 120.83 is: 181.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.96 : 643.35 = 120.83 : x
  2. Step 2: Convert to fraction form
    428.96/643.35 = 120.83/x
  3. Step 3: Cross multiply
    428.96x = 643.35 × 120.83
  4. Step 4: Simplify right side
    428.96x = 77,737.59
  5. Step 5: Solve for x
    x = 77,737.59/428.96
  6. Step 6: Final answer
    x = 181.22

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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.