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Finding the Fourth Proportional to 812.15, 1,120.76 and 439.12

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Solution

The fourth proportional to 812.15, 1,120.76 and 439.12 is: 605.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.15 : 1,120.76 = 439.12 : x
  2. Step 2: Convert to fraction form
    812.15/1,120.76 = 439.12/x
  3. Step 3: Cross multiply
    812.15x = 1,120.76 × 439.12
  4. Step 4: Simplify right side
    812.15x = 492,154.61
  5. Step 5: Solve for x
    x = 492,154.61/812.15
  6. Step 6: Final answer
    x = 605.99

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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.