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Finding the Fourth Proportional to 620.60, 856.05 and 399.47

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Solution

The fourth proportional to 620.60, 856.05 and 399.47 is: 551.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.60 : 856.05 = 399.47 : x
  2. Step 2: Convert to fraction form
    620.60/856.05 = 399.47/x
  3. Step 3: Cross multiply
    620.60x = 856.05 × 399.47
  4. Step 4: Simplify right side
    620.60x = 341,966.29
  5. Step 5: Solve for x
    x = 341,966.29/620.60
  6. Step 6: Final answer
    x = 551.03

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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.