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Finding the Fourth Proportional to 620.22, 856.37 and 399.30

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Solution

The fourth proportional to 620.22, 856.37 and 399.30 is: 551.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.22 : 856.37 = 399.30 : x
  2. Step 2: Convert to fraction form
    620.22/856.37 = 399.30/x
  3. Step 3: Cross multiply
    620.22x = 856.37 × 399.30
  4. Step 4: Simplify right side
    620.22x = 341,946.54
  5. Step 5: Solve for x
    x = 341,946.54/620.22
  6. Step 6: Final answer
    x = 551.33

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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.