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Finding the Fourth Proportional to 28.49, 42.63 and 20.86

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Solution

The fourth proportional to 28.49, 42.63 and 20.86 is: 31.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.49 : 42.63 = 20.86 : x
  2. Step 2: Convert to fraction form
    28.49/42.63 = 20.86/x
  3. Step 3: Cross multiply
    28.49x = 42.63 × 20.86
  4. Step 4: Simplify right side
    28.49x = 889.08
  5. Step 5: Solve for x
    x = 889.08/28.49
  6. Step 6: Final answer
    x = 31.21

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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.