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Finding the Fourth Proportional to 620.74, 855.96 and 399.50

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Solution

The fourth proportional to 620.74, 855.96 and 399.50 is: 550.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.74 : 855.96 = 399.50 : x
  2. Step 2: Convert to fraction form
    620.74/855.96 = 399.50/x
  3. Step 3: Cross multiply
    620.74x = 855.96 × 399.50
  4. Step 4: Simplify right side
    620.74x = 341,956.02
  5. Step 5: Solve for x
    x = 341,956.02/620.74
  6. Step 6: Final answer
    x = 550.88

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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.