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Finding the Fourth Proportional to 74.31, 111.45 and 20.20

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Solution

The fourth proportional to 74.31, 111.45 and 20.20 is: 30.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    74.31 : 111.45 = 20.20 : x
  2. Step 2: Convert to fraction form
    74.31/111.45 = 20.20/x
  3. Step 3: Cross multiply
    74.31x = 111.45 × 20.20
  4. Step 4: Simplify right side
    74.31x = 2,251.29
  5. Step 5: Solve for x
    x = 2,251.29/74.31
  6. Step 6: Final answer
    x = 30.30

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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.