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Finding the Fourth Proportional to 77.50, 115.64 and 68.79

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Solution

The fourth proportional to 77.50, 115.64 and 68.79 is: 102.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.50 : 115.64 = 68.79 : x
  2. Step 2: Convert to fraction form
    77.50/115.64 = 68.79/x
  3. Step 3: Cross multiply
    77.50x = 115.64 × 68.79
  4. Step 4: Simplify right side
    77.50x = 7,954.53
  5. Step 5: Solve for x
    x = 7,954.53/77.50
  6. Step 6: Final answer
    x = 102.64

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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.