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Finding the Fourth Proportional to 620.30, 856.20 and 399.32

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Solution

The fourth proportional to 620.30, 856.20 and 399.32 is: 551.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.30 : 856.20 = 399.32 : x
  2. Step 2: Convert to fraction form
    620.30/856.20 = 399.32/x
  3. Step 3: Cross multiply
    620.30x = 856.20 × 399.32
  4. Step 4: Simplify right side
    620.30x = 341,897.78
  5. Step 5: Solve for x
    x = 341,897.78/620.30
  6. Step 6: Final answer
    x = 551.18

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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.