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Finding the Fourth Proportional to 30.92, 42.66 and 20.57

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Solution

The fourth proportional to 30.92, 42.66 and 20.57 is: 28.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.92 : 42.66 = 20.57 : x
  2. Step 2: Convert to fraction form
    30.92/42.66 = 20.57/x
  3. Step 3: Cross multiply
    30.92x = 42.66 × 20.57
  4. Step 4: Simplify right side
    30.92x = 877.30
  5. Step 5: Solve for x
    x = 877.30/30.92
  6. Step 6: Final answer
    x = 28.38

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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.