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Finding the Fourth Proportional to 660.69, 990.71 and 221.79

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Solution

The fourth proportional to 660.69, 990.71 and 221.79 is: 332.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.69 : 990.71 = 221.79 : x
  2. Step 2: Convert to fraction form
    660.69/990.71 = 221.79/x
  3. Step 3: Cross multiply
    660.69x = 990.71 × 221.79
  4. Step 4: Simplify right side
    660.69x = 219,729.57
  5. Step 5: Solve for x
    x = 219,729.57/660.69
  6. Step 6: Final answer
    x = 332.58

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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.