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Finding the Fourth Proportional to 21.75, 30.01 and 13.55

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Solution

The fourth proportional to 21.75, 30.01 and 13.55 is: 18.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.75 : 30.01 = 13.55 : x
  2. Step 2: Convert to fraction form
    21.75/30.01 = 13.55/x
  3. Step 3: Cross multiply
    21.75x = 30.01 × 13.55
  4. Step 4: Simplify right side
    21.75x = 406.69
  5. Step 5: Solve for x
    x = 406.69/21.75
  6. Step 6: Final answer
    x = 18.69

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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.