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Finding the Fourth Proportional to 15.40, 21.25 and 11.75

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Solution

The fourth proportional to 15.40, 21.25 and 11.75 is: 16.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.40 : 21.25 = 11.75 : x
  2. Step 2: Convert to fraction form
    15.40/21.25 = 11.75/x
  3. Step 3: Cross multiply
    15.40x = 21.25 × 11.75
  4. Step 4: Simplify right side
    15.40x = 249.69
  5. Step 5: Solve for x
    x = 249.69/15.40
  6. Step 6: Final answer
    x = 16.21

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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.