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Finding the Fourth Proportional to 54.21, 81.36 and 20.00

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Solution

The fourth proportional to 54.21, 81.36 and 20.00 is: 30.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    54.21 : 81.36 = 20.00 : x
  2. Step 2: Convert to fraction form
    54.21/81.36 = 20.00/x
  3. Step 3: Cross multiply
    54.21x = 81.36 × 20.00
  4. Step 4: Simplify right side
    54.21x = 1,627.40
  5. Step 5: Solve for x
    x = 1,627.40/54.21
  6. Step 6: Final answer
    x = 30.02

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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.