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Finding the Fourth Proportional to 999.93, 1,378.42 and 645.82

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Solution

The fourth proportional to 999.93, 1,378.42 and 645.82 is: 890.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.93 : 1,378.42 = 645.82 : x
  2. Step 2: Convert to fraction form
    999.93/1,378.42 = 645.82/x
  3. Step 3: Cross multiply
    999.93x = 1,378.42 × 645.82
  4. Step 4: Simplify right side
    999.93x = 890,211.20
  5. Step 5: Solve for x
    x = 890,211.20/999.93
  6. Step 6: Final answer
    x = 890.27

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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.