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Finding the Fourth Proportional to 76.81, 115.18 and 28.71

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Solution

The fourth proportional to 76.81, 115.18 and 28.71 is: 43.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.81 : 115.18 = 28.71 : x
  2. Step 2: Convert to fraction form
    76.81/115.18 = 28.71/x
  3. Step 3: Cross multiply
    76.81x = 115.18 × 28.71
  4. Step 4: Simplify right side
    76.81x = 3,306.82
  5. Step 5: Solve for x
    x = 3,306.82/76.81
  6. Step 6: Final answer
    x = 43.05

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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.