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Finding the Fourth Proportional to 612.31, 845.12 and 391.21

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Solution

The fourth proportional to 612.31, 845.12 and 391.21 is: 539.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    612.31 : 845.12 = 391.21 : x
  2. Step 2: Convert to fraction form
    612.31/845.12 = 391.21/x
  3. Step 3: Cross multiply
    612.31x = 845.12 × 391.21
  4. Step 4: Simplify right side
    612.31x = 330,619.40
  5. Step 5: Solve for x
    x = 330,619.40/612.31
  6. Step 6: Final answer
    x = 539.95

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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.