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Finding the Fourth Proportional to 660.11, 989.84 and 221.21

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Solution

The fourth proportional to 660.11, 989.84 and 221.21 is: 331.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.11 : 989.84 = 221.21 : x
  2. Step 2: Convert to fraction form
    660.11/989.84 = 221.21/x
  3. Step 3: Cross multiply
    660.11x = 989.84 × 221.21
  4. Step 4: Simplify right side
    660.11x = 218,961.40
  5. Step 5: Solve for x
    x = 218,961.40/660.11
  6. Step 6: Final answer
    x = 331.70

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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.