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Finding the Fourth Proportional to 31.29, 43.45 and 30.79

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Solution

The fourth proportional to 31.29, 43.45 and 30.79 is: 42.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.29 : 43.45 = 30.79 : x
  2. Step 2: Convert to fraction form
    31.29/43.45 = 30.79/x
  3. Step 3: Cross multiply
    31.29x = 43.45 × 30.79
  4. Step 4: Simplify right side
    31.29x = 1,337.83
  5. Step 5: Solve for x
    x = 1,337.83/31.29
  6. Step 6: Final answer
    x = 42.76

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.