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Finding the Fourth Proportional to 27.91, 38.55 and 21.79

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Solution

The fourth proportional to 27.91, 38.55 and 21.79 is: 30.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    27.91 : 38.55 = 21.79 : x
  2. Step 2: Convert to fraction form
    27.91/38.55 = 21.79/x
  3. Step 3: Cross multiply
    27.91x = 38.55 × 21.79
  4. Step 4: Simplify right side
    27.91x = 840.00
  5. Step 5: Solve for x
    x = 840.00/27.91
  6. Step 6: Final answer
    x = 30.10

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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.