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Finding the Fourth Proportional to 429.39, 643.94 and 121.22

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Solution

The fourth proportional to 429.39, 643.94 and 121.22 is: 181.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.39 : 643.94 = 121.22 : x
  2. Step 2: Convert to fraction form
    429.39/643.94 = 121.22/x
  3. Step 3: Cross multiply
    429.39x = 643.94 × 121.22
  4. Step 4: Simplify right side
    429.39x = 78,054.58
  5. Step 5: Solve for x
    x = 78,054.58/429.39
  6. Step 6: Final answer
    x = 181.78

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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.