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Finding the Fourth Proportional to 659.89, 989.80 and 221.11

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Solution

The fourth proportional to 659.89, 989.80 and 221.11 is: 331.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    659.89 : 989.80 = 221.11 : x
  2. Step 2: Convert to fraction form
    659.89/989.80 = 221.11/x
  3. Step 3: Cross multiply
    659.89x = 989.80 × 221.11
  4. Step 4: Simplify right side
    659.89x = 218,854.68
  5. Step 5: Solve for x
    x = 218,854.68/659.89
  6. Step 6: Final answer
    x = 331.65

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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.