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Finding the Fourth Proportional to 620.84, 856.46 and 399.72

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Solution

The fourth proportional to 620.84, 856.46 and 399.72 is: 551.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.84 : 856.46 = 399.72 : x
  2. Step 2: Convert to fraction form
    620.84/856.46 = 399.72/x
  3. Step 3: Cross multiply
    620.84x = 856.46 × 399.72
  4. Step 4: Simplify right side
    620.84x = 342,344.19
  5. Step 5: Solve for x
    x = 342,344.19/620.84
  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.