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Finding the Fourth Proportional to 54.20, 74.80 and 30.89

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Solution

The fourth proportional to 54.20, 74.80 and 30.89 is: 42.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    54.20 : 74.80 = 30.89 : x
  2. Step 2: Convert to fraction form
    54.20/74.80 = 30.89/x
  3. Step 3: Cross multiply
    54.20x = 74.80 × 30.89
  4. Step 4: Simplify right side
    54.20x = 2,310.42
  5. Step 5: Solve for x
    x = 2,310.42/54.20
  6. Step 6: Final answer
    x = 42.63

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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.