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Finding the Fourth Proportional to 620.32, 855.95 and 399.57

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Solution

The fourth proportional to 620.32, 855.95 and 399.57 is: 551.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.32 : 855.95 = 399.57 : x
  2. Step 2: Convert to fraction form
    620.32/855.95 = 399.57/x
  3. Step 3: Cross multiply
    620.32x = 855.95 × 399.57
  4. Step 4: Simplify right side
    620.32x = 342,011.94
  5. Step 5: Solve for x
    x = 342,011.94/620.32
  6. Step 6: Final answer
    x = 551.35

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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.