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Finding the Fourth Proportional to 999.12, 1,378 and 920.54

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Solution

The fourth proportional to 999.12, 1,378 and 920.54 is: 1,269.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.12 : 1,378 = 920.54 : x
  2. Step 2: Convert to fraction form
    999.12/1,378 = 920.54/x
  3. Step 3: Cross multiply
    999.12x = 1,378 × 920.54
  4. Step 4: Simplify right side
    999.12x = 1,268,504.12
  5. Step 5: Solve for x
    x = 1,268,504.12/999.12
  6. Step 6: Final answer
    x = 1,269.62

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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.