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Finding the Fourth Proportional to 27.78, 38.28 and 21.64

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Solution

The fourth proportional to 27.78, 38.28 and 21.64 is: 29.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    27.78 : 38.28 = 21.64 : x
  2. Step 2: Convert to fraction form
    27.78/38.28 = 21.64/x
  3. Step 3: Cross multiply
    27.78x = 38.28 × 21.64
  4. Step 4: Simplify right side
    27.78x = 828.27
  5. Step 5: Solve for x
    x = 828.27/27.78
  6. Step 6: Final answer
    x = 29.82

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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.