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Finding the Fourth Proportional to 620.88, 857.07 and 399.90

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Solution

The fourth proportional to 620.88, 857.07 and 399.90 is: 552.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.88 : 857.07 = 399.90 : x
  2. Step 2: Convert to fraction form
    620.88/857.07 = 399.90/x
  3. Step 3: Cross multiply
    620.88x = 857.07 × 399.90
  4. Step 4: Simplify right side
    620.88x = 342,745.51
  5. Step 5: Solve for x
    x = 342,745.51/620.88
  6. Step 6: Final answer
    x = 552.04

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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.