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Finding the Fourth Proportional to 13.59, 20.40 and 12.45

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Solution

The fourth proportional to 13.59, 20.40 and 12.45 is: 18.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.59 : 20.40 = 12.45 : x
  2. Step 2: Convert to fraction form
    13.59/20.40 = 12.45/x
  3. Step 3: Cross multiply
    13.59x = 20.40 × 12.45
  4. Step 4: Simplify right side
    13.59x = 254.01
  5. Step 5: Solve for x
    x = 254.01/13.59
  6. Step 6: Final answer
    x = 18.69

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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.