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Finding the Fourth Proportional to 20.15, 30.16 and 12.81

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Solution

The fourth proportional to 20.15, 30.16 and 12.81 is: 19.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.15 : 30.16 = 12.81 : x
  2. Step 2: Convert to fraction form
    20.15/30.16 = 12.81/x
  3. Step 3: Cross multiply
    20.15x = 30.16 × 12.81
  4. Step 4: Simplify right side
    20.15x = 386.24
  5. Step 5: Solve for x
    x = 386.24/20.15
  6. Step 6: Final answer
    x = 19.16

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.