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Finding the Fourth Proportional to 28.81, 39.81 and 28.15

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Solution

The fourth proportional to 28.81, 39.81 and 28.15 is: 38.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.81 : 39.81 = 28.15 : x
  2. Step 2: Convert to fraction form
    28.81/39.81 = 28.15/x
  3. Step 3: Cross multiply
    28.81x = 39.81 × 28.15
  4. Step 4: Simplify right side
    28.81x = 1,120.65
  5. Step 5: Solve for x
    x = 1,120.65/28.81
  6. Step 6: Final answer
    x = 38.90

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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.