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Finding the Fourth Proportional to 612.68, 845.18 and 391.40

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Solution

The fourth proportional to 612.68, 845.18 and 391.40 is: 539.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    612.68 : 845.18 = 391.40 : x
  2. Step 2: Convert to fraction form
    612.68/845.18 = 391.40/x
  3. Step 3: Cross multiply
    612.68x = 845.18 × 391.40
  4. Step 4: Simplify right side
    612.68x = 330,797.27
  5. Step 5: Solve for x
    x = 330,797.27/612.68
  6. Step 6: Final answer
    x = 539.92

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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.