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Finding the Fourth Proportional to 429.92, 644.78 and 121.80

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Solution

The fourth proportional to 429.92, 644.78 and 121.80 is: 182.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.92 : 644.78 = 121.80 : x
  2. Step 2: Convert to fraction form
    429.92/644.78 = 121.80/x
  3. Step 3: Cross multiply
    429.92x = 644.78 × 121.80
  4. Step 4: Simplify right side
    429.92x = 78,533.60
  5. Step 5: Solve for x
    x = 78,533.60/429.92
  6. Step 6: Final answer
    x = 182.67

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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.