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Finding the Fourth Proportional to 621, 856.17 and 399.96

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Solution

The fourth proportional to 621, 856.17 and 399.96 is: 551.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    621 : 856.17 = 399.96 : x
  2. Step 2: Convert to fraction form
    621/856.17 = 399.96/x
  3. Step 3: Cross multiply
    621x = 856.17 × 399.96
  4. Step 4: Simplify right side
    621x = 342,433.75
  5. Step 5: Solve for x
    x = 342,433.75/621
  6. Step 6: Final answer
    x = 551.42

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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.