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Finding the Fourth Proportional to 20.94, 28.72 and 20.91

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Solution

The fourth proportional to 20.94, 28.72 and 20.91 is: 28.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.94 : 28.72 = 20.91 : x
  2. Step 2: Convert to fraction form
    20.94/28.72 = 20.91/x
  3. Step 3: Cross multiply
    20.94x = 28.72 × 20.91
  4. Step 4: Simplify right side
    20.94x = 600.54
  5. Step 5: Solve for x
    x = 600.54/20.94
  6. Step 6: Final answer
    x = 28.68

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.