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Finding the Fourth Proportional to 27.90, 38.48 and 20.61

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Solution

The fourth proportional to 27.90, 38.48 and 20.61 is: 28.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    27.90 : 38.48 = 20.61 : x
  2. Step 2: Convert to fraction form
    27.90/38.48 = 20.61/x
  3. Step 3: Cross multiply
    27.90x = 38.48 × 20.61
  4. Step 4: Simplify right side
    27.90x = 793.07
  5. Step 5: Solve for x
    x = 793.07/27.90
  6. Step 6: Final answer
    x = 28.43

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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.