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Finding the Fourth Proportional to 20.43, 28.18 and 13.05

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Solution

The fourth proportional to 20.43, 28.18 and 13.05 is: 18.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.43 : 28.18 = 13.05 : x
  2. Step 2: Convert to fraction form
    20.43/28.18 = 13.05/x
  3. Step 3: Cross multiply
    20.43x = 28.18 × 13.05
  4. Step 4: Simplify right side
    20.43x = 367.75
  5. Step 5: Solve for x
    x = 367.75/20.43
  6. Step 6: Final answer
    x = 18.00

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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.