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Finding the Fourth Proportional to 429.22, 643.76 and 121.05

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Solution

The fourth proportional to 429.22, 643.76 and 121.05 is: 181.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.22 : 643.76 = 121.05 : x
  2. Step 2: Convert to fraction form
    429.22/643.76 = 121.05/x
  3. Step 3: Cross multiply
    429.22x = 643.76 × 121.05
  4. Step 4: Simplify right side
    429.22x = 77,927.15
  5. Step 5: Solve for x
    x = 77,927.15/429.22
  6. Step 6: Final answer
    x = 181.56

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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.