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Finding the Fourth Proportional to 290.80, 398.42 and 286.75

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Solution

The fourth proportional to 290.80, 398.42 and 286.75 is: 392.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    290.80 : 398.42 = 286.75 : x
  2. Step 2: Convert to fraction form
    290.80/398.42 = 286.75/x
  3. Step 3: Cross multiply
    290.80x = 398.42 × 286.75
  4. Step 4: Simplify right side
    290.80x = 114,246.94
  5. Step 5: Solve for x
    x = 114,246.94/290.80
  6. Step 6: Final answer
    x = 392.87

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.