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Finding the Fourth Proportional to 287.38, 431.09 and 81.95

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Solution

The fourth proportional to 287.38, 431.09 and 81.95 is: 122.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.38 : 431.09 = 81.95 : x
  2. Step 2: Convert to fraction form
    287.38/431.09 = 81.95/x
  3. Step 3: Cross multiply
    287.38x = 431.09 × 81.95
  4. Step 4: Simplify right side
    287.38x = 35,327.83
  5. Step 5: Solve for x
    x = 35,327.83/287.38
  6. Step 6: Final answer
    x = 122.93

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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.