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Finding the Fourth Proportional to 390.78, 584.94 and 286.44

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Solution

The fourth proportional to 390.78, 584.94 and 286.44 is: 428.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.78 : 584.94 = 286.44 : x
  2. Step 2: Convert to fraction form
    390.78/584.94 = 286.44/x
  3. Step 3: Cross multiply
    390.78x = 584.94 × 286.44
  4. Step 4: Simplify right side
    390.78x = 167,550.21
  5. Step 5: Solve for x
    x = 167,550.21/390.78
  6. Step 6: Final answer
    x = 428.76

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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.