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Finding the Fourth Proportional to 30.96, 42.74 and 20.05

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Solution

The fourth proportional to 30.96, 42.74 and 20.05 is: 27.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.96 : 42.74 = 20.05 : x
  2. Step 2: Convert to fraction form
    30.96/42.74 = 20.05/x
  3. Step 3: Cross multiply
    30.96x = 42.74 × 20.05
  4. Step 4: Simplify right side
    30.96x = 856.94
  5. Step 5: Solve for x
    x = 856.94/30.96
  6. Step 6: Final answer
    x = 27.68

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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.