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Finding the Fourth Proportional to 18.39, 25.31 and 15.31

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Solution

The fourth proportional to 18.39, 25.31 and 15.31 is: 21.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    18.39 : 25.31 = 15.31 : x
  2. Step 2: Convert to fraction form
    18.39/25.31 = 15.31/x
  3. Step 3: Cross multiply
    18.39x = 25.31 × 15.31
  4. Step 4: Simplify right side
    18.39x = 387.42
  5. Step 5: Solve for x
    x = 387.42/18.39
  6. Step 6: Final answer
    x = 21.07

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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.