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Finding the Fourth Proportional to 660.20, 990.30 and 416.39

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Solution

The fourth proportional to 660.20, 990.30 and 416.39 is: 624.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.20 : 990.30 = 416.39 : x
  2. Step 2: Convert to fraction form
    660.20/990.30 = 416.39/x
  3. Step 3: Cross multiply
    660.20x = 990.30 × 416.39
  4. Step 4: Simplify right side
    660.20x = 412,351.02
  5. Step 5: Solve for x
    x = 412,351.02/660.20
  6. Step 6: Final answer
    x = 624.59

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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.