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Finding the Fourth Proportional to 54.79, 82.16 and 20.55

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Solution

The fourth proportional to 54.79, 82.16 and 20.55 is: 30.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    54.79 : 82.16 = 20.55 : x
  2. Step 2: Convert to fraction form
    54.79/82.16 = 20.55/x
  3. Step 3: Cross multiply
    54.79x = 82.16 × 20.55
  4. Step 4: Simplify right side
    54.79x = 1,688.17
  5. Step 5: Solve for x
    x = 1,688.17/54.79
  6. Step 6: Final answer
    x = 30.81

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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.