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Finding the Fourth Proportional to 621.11, 930.94 and 390.05

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Solution

The fourth proportional to 621.11, 930.94 and 390.05 is: 584.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.11 : 930.94 = 390.05 : x
  2. Step 2: Convert to fraction form
    621.11/930.94 = 390.05/x
  3. Step 3: Cross multiply
    621.11x = 930.94 × 390.05
  4. Step 4: Simplify right side
    621.11x = 363,113.15
  5. Step 5: Solve for x
    x = 363,113.15/621.11
  6. Step 6: Final answer
    x = 584.62

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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.