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Finding the Fourth Proportional to 999.15, 1,379.44 and 645.24

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Solution

The fourth proportional to 999.15, 1,379.44 and 645.24 is: 890.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.15 : 1,379.44 = 645.24 : x
  2. Step 2: Convert to fraction form
    999.15/1,379.44 = 645.24/x
  3. Step 3: Cross multiply
    999.15x = 1,379.44 × 645.24
  4. Step 4: Simplify right side
    999.15x = 890,069.87
  5. Step 5: Solve for x
    x = 890,069.87/999.15
  6. Step 6: Final answer
    x = 890.83

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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.