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Finding the Fourth Proportional to 31.78, 43.77 and 28.14

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Solution

The fourth proportional to 31.78, 43.77 and 28.14 is: 38.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.78 : 43.77 = 28.14 : x
  2. Step 2: Convert to fraction form
    31.78/43.77 = 28.14/x
  3. Step 3: Cross multiply
    31.78x = 43.77 × 28.14
  4. Step 4: Simplify right side
    31.78x = 1,231.69
  5. Step 5: Solve for x
    x = 1,231.69/31.78
  6. Step 6: Final answer
    x = 38.76

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.