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Finding the Fourth Proportional to 25.20, 34.78 and 15.50

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Solution

The fourth proportional to 25.20, 34.78 and 15.50 is: 21.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    25.20 : 34.78 = 15.50 : x
  2. Step 2: Convert to fraction form
    25.20/34.78 = 15.50/x
  3. Step 3: Cross multiply
    25.20x = 34.78 × 15.50
  4. Step 4: Simplify right side
    25.20x = 539.09
  5. Step 5: Solve for x
    x = 539.09/25.20
  6. Step 6: Final answer
    x = 21.39

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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.