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Finding the Fourth Proportional to 659.50, 989.39 and 220.78

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Solution

The fourth proportional to 659.50, 989.39 and 220.78 is: 331.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    659.50 : 989.39 = 220.78 : x
  2. Step 2: Convert to fraction form
    659.50/989.39 = 220.78/x
  3. Step 3: Cross multiply
    659.50x = 989.39 × 220.78
  4. Step 4: Simplify right side
    659.50x = 218,431.47
  5. Step 5: Solve for x
    x = 218,431.47/659.50
  6. Step 6: Final answer
    x = 331.21

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1.5x scale

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.