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Finding the Fourth Proportional to 77.21, 115.28 and 67.56

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Solution

The fourth proportional to 77.21, 115.28 and 67.56 is: 100.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.21 : 115.28 = 67.56 : x
  2. Step 2: Convert to fraction form
    77.21/115.28 = 67.56/x
  3. Step 3: Cross multiply
    77.21x = 115.28 × 67.56
  4. Step 4: Simplify right side
    77.21x = 7,788.32
  5. Step 5: Solve for x
    x = 7,788.32/77.21
  6. Step 6: Final answer
    x = 100.87

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.