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Finding the Fourth Proportional to 18.90, 28.34 and 9.90

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Solution

The fourth proportional to 18.90, 28.34 and 9.90 is: 14.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    18.90 : 28.34 = 9.90 : x
  2. Step 2: Convert to fraction form
    18.90/28.34 = 9.90/x
  3. Step 3: Cross multiply
    18.90x = 28.34 × 9.90
  4. Step 4: Simplify right side
    18.90x = 280.52
  5. Step 5: Solve for x
    x = 280.52/18.90
  6. Step 6: Final answer
    x = 14.84

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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.