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Finding the Fourth Proportional to 28.52, 42.67 and 20.90

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Solution

The fourth proportional to 28.52, 42.67 and 20.90 is: 31.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.52 : 42.67 = 20.90 : x
  2. Step 2: Convert to fraction form
    28.52/42.67 = 20.90/x
  3. Step 3: Cross multiply
    28.52x = 42.67 × 20.90
  4. Step 4: Simplify right side
    28.52x = 891.49
  5. Step 5: Solve for x
    x = 891.49/28.52
  6. Step 6: Final answer
    x = 31.26

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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.