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Finding the Fourth Proportional to 29.50, 40.72 and 20.90

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Solution

The fourth proportional to 29.50, 40.72 and 20.90 is: 28.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    29.50 : 40.72 = 20.90 : x
  2. Step 2: Convert to fraction form
    29.50/40.72 = 20.90/x
  3. Step 3: Cross multiply
    29.50x = 40.72 × 20.90
  4. Step 4: Simplify right side
    29.50x = 851.05
  5. Step 5: Solve for x
    x = 851.05/29.50
  6. Step 6: Final answer
    x = 28.85

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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.