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Finding the Fourth Proportional to 21.75, 29.96 and 18.81

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Solution

The fourth proportional to 21.75, 29.96 and 18.81 is: 25.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.75 : 29.96 = 18.81 : x
  2. Step 2: Convert to fraction form
    21.75/29.96 = 18.81/x
  3. Step 3: Cross multiply
    21.75x = 29.96 × 18.81
  4. Step 4: Simplify right side
    21.75x = 563.45
  5. Step 5: Solve for x
    x = 563.45/21.75
  6. Step 6: Final answer
    x = 25.91

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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.