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Finding the Fourth Proportional to 620.86, 930.21 and 390.28

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Solution

The fourth proportional to 620.86, 930.21 and 390.28 is: 584.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.86 : 930.21 = 390.28 : x
  2. Step 2: Convert to fraction form
    620.86/930.21 = 390.28/x
  3. Step 3: Cross multiply
    620.86x = 930.21 × 390.28
  4. Step 4: Simplify right side
    620.86x = 363,042.36
  5. Step 5: Solve for x
    x = 363,042.36/620.86
  6. Step 6: Final answer
    x = 584.74

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.