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Finding the Fourth Proportional to 1,188.80, 1,640.31 and 664.73

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Solution

The fourth proportional to 1,188.80, 1,640.31 and 664.73 is: 917.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,188.80 : 1,640.31 = 664.73 : x
  2. Step 2: Convert to fraction form
    1,188.80/1,640.31 = 664.73/x
  3. Step 3: Cross multiply
    1,188.80x = 1,640.31 × 664.73
  4. Step 4: Simplify right side
    1,188.80x = 1,090,363.27
  5. Step 5: Solve for x
    x = 1,090,363.27/1,188.80
  6. Step 6: Final answer
    x = 917.20

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.