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Finding the Fourth Proportional to 25.21, 34.81 and 19.78

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Solution

The fourth proportional to 25.21, 34.81 and 19.78 is: 27.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    25.21 : 34.81 = 19.78 : x
  2. Step 2: Convert to fraction form
    25.21/34.81 = 19.78/x
  3. Step 3: Cross multiply
    25.21x = 34.81 × 19.78
  4. Step 4: Simplify right side
    25.21x = 688.52
  5. Step 5: Solve for x
    x = 688.52/25.21
  6. Step 6: Final answer
    x = 27.31

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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.