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Finding the Fourth Proportional to 13.11, 19.78 and 13.11

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Solution

The fourth proportional to 13.11, 19.78 and 13.11 is: 19.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.11 : 19.78 = 13.11 : x
  2. Step 2: Convert to fraction form
    13.11/19.78 = 13.11/x
  3. Step 3: Cross multiply
    13.11x = 19.78 × 13.11
  4. Step 4: Simplify right side
    13.11x = 259.32
  5. Step 5: Solve for x
    x = 259.32/13.11
  6. Step 6: Final answer
    x = 19.78

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.