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Finding the Fourth Proportional to 660.50, 990.78 and 221.80

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Solution

The fourth proportional to 660.50, 990.78 and 221.80 is: 332.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.50 : 990.78 = 221.80 : x
  2. Step 2: Convert to fraction form
    660.50/990.78 = 221.80/x
  3. Step 3: Cross multiply
    660.50x = 990.78 × 221.80
  4. Step 4: Simplify right side
    660.50x = 219,755.00
  5. Step 5: Solve for x
    x = 219,755.00/660.50
  6. Step 6: Final answer
    x = 332.71

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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.