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Finding the Fourth Proportional to 77.19, 115.78 and 20.19

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Solution

The fourth proportional to 77.19, 115.78 and 20.19 is: 30.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.19 : 115.78 = 20.19 : x
  2. Step 2: Convert to fraction form
    77.19/115.78 = 20.19/x
  3. Step 3: Cross multiply
    77.19x = 115.78 × 20.19
  4. Step 4: Simplify right side
    77.19x = 2,337.33
  5. Step 5: Solve for x
    x = 2,337.33/77.19
  6. Step 6: Final answer
    x = 30.28

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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.