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Finding the Fourth Proportional to 1,072.20, 1,608.30 and 640.20

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Solution

The fourth proportional to 1,072.20, 1,608.30 and 640.20 is: 960.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,072.20 : 1,608.30 = 640.20 : x
  2. Step 2: Convert to fraction form
    1,072.20/1,608.30 = 640.20/x
  3. Step 3: Cross multiply
    1,072.20x = 1,608.30 × 640.20
  4. Step 4: Simplify right side
    1,072.20x = 1,029,633.66
  5. Step 5: Solve for x
    x = 1,029,633.66/1,072.20
  6. Step 6: Final answer
    x = 960.30

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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.