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Finding the Fourth Proportional to 429.22, 643.81 and 121.09

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Solution

The fourth proportional to 429.22, 643.81 and 121.09 is: 181.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.22 : 643.81 = 121.09 : x
  2. Step 2: Convert to fraction form
    429.22/643.81 = 121.09/x
  3. Step 3: Cross multiply
    429.22x = 643.81 × 121.09
  4. Step 4: Simplify right side
    429.22x = 77,958.95
  5. Step 5: Solve for x
    x = 77,958.95/429.22
  6. Step 6: Final answer
    x = 181.63

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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.