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Finding the Fourth Proportional to 621.09, 856.81 and 399.97

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Solution

The fourth proportional to 621.09, 856.81 and 399.97 is: 551.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.09 : 856.81 = 399.97 : x
  2. Step 2: Convert to fraction form
    621.09/856.81 = 399.97/x
  3. Step 3: Cross multiply
    621.09x = 856.81 × 399.97
  4. Step 4: Simplify right side
    621.09x = 342,696.30
  5. Step 5: Solve for x
    x = 342,696.30/621.09
  6. Step 6: Final answer
    x = 551.77

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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.