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Finding the Fourth Proportional to 660, 990.06 and 221.25

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Solution

The fourth proportional to 660, 990.06 and 221.25 is: 331.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    660 : 990.06 = 221.25 : x
  2. Step 2: Convert to fraction form
    660/990.06 = 221.25/x
  3. Step 3: Cross multiply
    660x = 990.06 × 221.25
  4. Step 4: Simplify right side
    660x = 219,050.78
  5. Step 5: Solve for x
    x = 219,050.78/660
  6. Step 6: Final answer
    x = 331.90

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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.