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Finding the Fourth Proportional to 287.27, 430.92 and 81.86

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Solution

The fourth proportional to 287.27, 430.92 and 81.86 is: 122.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.27 : 430.92 = 81.86 : x
  2. Step 2: Convert to fraction form
    287.27/430.92 = 81.86/x
  3. Step 3: Cross multiply
    287.27x = 430.92 × 81.86
  4. Step 4: Simplify right side
    287.27x = 35,272.96
  5. Step 5: Solve for x
    x = 35,272.96/287.27
  6. Step 6: Final answer
    x = 122.79

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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.