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Finding the Fourth Proportional to 31.28, 42.92 and 30.48

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Solution

The fourth proportional to 31.28, 42.92 and 30.48 is: 41.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.28 : 42.92 = 30.48 : x
  2. Step 2: Convert to fraction form
    31.28/42.92 = 30.48/x
  3. Step 3: Cross multiply
    31.28x = 42.92 × 30.48
  4. Step 4: Simplify right side
    31.28x = 1,308.20
  5. Step 5: Solve for x
    x = 1,308.20/31.28
  6. Step 6: Final answer
    x = 41.82

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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.