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Finding the Fourth Proportional to 18.87, 28.31 and 11.65

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Solution

The fourth proportional to 18.87, 28.31 and 11.65 is: 17.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    18.87 : 28.31 = 11.65 : x
  2. Step 2: Convert to fraction form
    18.87/28.31 = 11.65/x
  3. Step 3: Cross multiply
    18.87x = 28.31 × 11.65
  4. Step 4: Simplify right side
    18.87x = 329.81
  5. Step 5: Solve for x
    x = 329.81/18.87
  6. Step 6: Final answer
    x = 17.48

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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.