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Finding the Fourth Proportional to 28.21, 42.27 and 12.15

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Solution

The fourth proportional to 28.21, 42.27 and 12.15 is: 18.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.21 : 42.27 = 12.15 : x
  2. Step 2: Convert to fraction form
    28.21/42.27 = 12.15/x
  3. Step 3: Cross multiply
    28.21x = 42.27 × 12.15
  4. Step 4: Simplify right side
    28.21x = 513.58
  5. Step 5: Solve for x
    x = 513.58/28.21
  6. Step 6: Final answer
    x = 18.21

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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.