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Finding the Fourth Proportional to 429.56, 644.30 and 121.40

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Solution

The fourth proportional to 429.56, 644.30 and 121.40 is: 182.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.56 : 644.30 = 121.40 : x
  2. Step 2: Convert to fraction form
    429.56/644.30 = 121.40/x
  3. Step 3: Cross multiply
    429.56x = 644.30 × 121.40
  4. Step 4: Simplify right side
    429.56x = 78,218.02
  5. Step 5: Solve for x
    x = 78,218.02/429.56
  6. Step 6: Final answer
    x = 182.09

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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.