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Finding the Fourth Proportional to 20.10, 27.72 and 12.80

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Solution

The fourth proportional to 20.10, 27.72 and 12.80 is: 17.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.10 : 27.72 = 12.80 : x
  2. Step 2: Convert to fraction form
    20.10/27.72 = 12.80/x
  3. Step 3: Cross multiply
    20.10x = 27.72 × 12.80
  4. Step 4: Simplify right side
    20.10x = 354.82
  5. Step 5: Solve for x
    x = 354.82/20.10
  6. Step 6: Final answer
    x = 17.65

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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.