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Finding the Fourth Proportional to 19.20, 28.76 and 11.15

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Solution

The fourth proportional to 19.20, 28.76 and 11.15 is: 16.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    19.20 : 28.76 = 11.15 : x
  2. Step 2: Convert to fraction form
    19.20/28.76 = 11.15/x
  3. Step 3: Cross multiply
    19.20x = 28.76 × 11.15
  4. Step 4: Simplify right side
    19.20x = 320.47
  5. Step 5: Solve for x
    x = 320.47/19.20
  6. Step 6: Final answer
    x = 16.69

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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.