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Finding the Fourth Proportional to 13.57, 18.72 and 7.82

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Solution

The fourth proportional to 13.57, 18.72 and 7.82 is: 10.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.57 : 18.72 = 7.82 : x
  2. Step 2: Convert to fraction form
    13.57/18.72 = 7.82/x
  3. Step 3: Cross multiply
    13.57x = 18.72 × 7.82
  4. Step 4: Simplify right side
    13.57x = 146.30
  5. Step 5: Solve for x
    x = 146.30/13.57
  6. Step 6: Final answer
    x = 10.78

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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.