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Finding the Fourth Proportional to 20.16, 30.40 and 18.86

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Solution

The fourth proportional to 20.16, 30.40 and 18.86 is: 28.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.16 : 30.40 = 18.86 : x
  2. Step 2: Convert to fraction form
    20.16/30.40 = 18.86/x
  3. Step 3: Cross multiply
    20.16x = 30.40 × 18.86
  4. Step 4: Simplify right side
    20.16x = 573.14
  5. Step 5: Solve for x
    x = 573.14/20.16
  6. Step 6: Final answer
    x = 28.43

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.