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Finding the Fourth Proportional to 999.49, 1,379.93 and 685.28

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Solution

The fourth proportional to 999.49, 1,379.93 and 685.28 is: 946.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.49 : 1,379.93 = 685.28 : x
  2. Step 2: Convert to fraction form
    999.49/1,379.93 = 685.28/x
  3. Step 3: Cross multiply
    999.49x = 1,379.93 × 685.28
  4. Step 4: Simplify right side
    999.49x = 945,638.43
  5. Step 5: Solve for x
    x = 945,638.43/999.49
  6. Step 6: Final answer
    x = 946.12

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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.