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Finding the Fourth Proportional to 13.28, 18.42 and 13

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Solution

The fourth proportional to 13.28, 18.42 and 13 is: 18.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.28 : 18.42 = 13 : x
  2. Step 2: Convert to fraction form
    13.28/18.42 = 13/x
  3. Step 3: Cross multiply
    13.28x = 18.42 × 13
  4. Step 4: Simplify right side
    13.28x = 239.46
  5. Step 5: Solve for x
    x = 239.46/13.28
  6. Step 6: Final answer
    x = 18.03

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.