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Finding the Fourth Proportional to 55.21, 82.80 and 20.99

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Solution

The fourth proportional to 55.21, 82.80 and 20.99 is: 31.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    55.21 : 82.80 = 20.99 : x
  2. Step 2: Convert to fraction form
    55.21/82.80 = 20.99/x
  3. Step 3: Cross multiply
    55.21x = 82.80 × 20.99
  4. Step 4: Simplify right side
    55.21x = 1,737.97
  5. Step 5: Solve for x
    x = 1,737.97/55.21
  6. Step 6: Final answer
    x = 31.48

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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.