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Finding the Fourth Proportional to 620.19, 855.72 and 399.06

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Solution

The fourth proportional to 620.19, 855.72 and 399.06 is: 550.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.19 : 855.72 = 399.06 : x
  2. Step 2: Convert to fraction form
    620.19/855.72 = 399.06/x
  3. Step 3: Cross multiply
    620.19x = 855.72 × 399.06
  4. Step 4: Simplify right side
    620.19x = 341,483.62
  5. Step 5: Solve for x
    x = 341,483.62/620.19
  6. Step 6: Final answer
    x = 550.61

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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.