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Finding the Fourth Proportional to 999.73, 1,380.21 and 663.65

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Solution

The fourth proportional to 999.73, 1,380.21 and 663.65 is: 916.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.73 : 1,380.21 = 663.65 : x
  2. Step 2: Convert to fraction form
    999.73/1,380.21 = 663.65/x
  3. Step 3: Cross multiply
    999.73x = 1,380.21 × 663.65
  4. Step 4: Simplify right side
    999.73x = 915,973.05
  5. Step 5: Solve for x
    x = 915,973.05/999.73
  6. Step 6: Final answer
    x = 916.22

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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.