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Finding the Fourth Proportional to 18.79, 28.20 and 13.45

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Solution

The fourth proportional to 18.79, 28.20 and 13.45 is: 20.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    18.79 : 28.20 = 13.45 : x
  2. Step 2: Convert to fraction form
    18.79/28.20 = 13.45/x
  3. Step 3: Cross multiply
    18.79x = 28.20 × 13.45
  4. Step 4: Simplify right side
    18.79x = 379.08
  5. Step 5: Solve for x
    x = 379.08/18.79
  6. Step 6: Final answer
    x = 20.18

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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.