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Finding the Fourth Proportional to 13.25, 19.86 and 12.80

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Solution

The fourth proportional to 13.25, 19.86 and 12.80 is: 19.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.25 : 19.86 = 12.80 : x
  2. Step 2: Convert to fraction form
    13.25/19.86 = 12.80/x
  3. Step 3: Cross multiply
    13.25x = 19.86 × 12.80
  4. Step 4: Simplify right side
    13.25x = 254.21
  5. Step 5: Solve for x
    x = 254.21/13.25
  6. Step 6: Final answer
    x = 19.19

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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.