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Finding the Fourth Proportional to 19.21, 28.78 and 15.39

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Solution

The fourth proportional to 19.21, 28.78 and 15.39 is: 23.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    19.21 : 28.78 = 15.39 : x
  2. Step 2: Convert to fraction form
    19.21/28.78 = 15.39/x
  3. Step 3: Cross multiply
    19.21x = 28.78 × 15.39
  4. Step 4: Simplify right side
    19.21x = 442.93
  5. Step 5: Solve for x
    x = 442.93/19.21
  6. Step 6: Final answer
    x = 23.05

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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.