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Finding the Fourth Proportional to 28.61, 39.46 and 20.45

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Solution

The fourth proportional to 28.61, 39.46 and 20.45 is: 28.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.61 : 39.46 = 20.45 : x
  2. Step 2: Convert to fraction form
    28.61/39.46 = 20.45/x
  3. Step 3: Cross multiply
    28.61x = 39.46 × 20.45
  4. Step 4: Simplify right side
    28.61x = 806.96
  5. Step 5: Solve for x
    x = 806.96/28.61
  6. Step 6: Final answer
    x = 28.21

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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.