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Finding the Fourth Proportional to 54.95, 82.40 and 20.71

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Solution

The fourth proportional to 54.95, 82.40 and 20.71 is: 31.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    54.95 : 82.40 = 20.71 : x
  2. Step 2: Convert to fraction form
    54.95/82.40 = 20.71/x
  3. Step 3: Cross multiply
    54.95x = 82.40 × 20.71
  4. Step 4: Simplify right side
    54.95x = 1,706.09
  5. Step 5: Solve for x
    x = 1,706.09/54.95
  6. Step 6: Final answer
    x = 31.05

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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.