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Finding the Fourth Proportional to 612.84, 845.86 and 399.78

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Solution

The fourth proportional to 612.84, 845.86 and 399.78 is: 551.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    612.84 : 845.86 = 399.78 : x
  2. Step 2: Convert to fraction form
    612.84/845.86 = 399.78/x
  3. Step 3: Cross multiply
    612.84x = 845.86 × 399.78
  4. Step 4: Simplify right side
    612.84x = 338,157.91
  5. Step 5: Solve for x
    x = 338,157.91/612.84
  6. Step 6: Final answer
    x = 551.79

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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.