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Finding the Fourth Proportional to 77.64, 115.79 and 69.60

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Solution

The fourth proportional to 77.64, 115.79 and 69.60 is: 103.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.64 : 115.79 = 69.60 : x
  2. Step 2: Convert to fraction form
    77.64/115.79 = 69.60/x
  3. Step 3: Cross multiply
    77.64x = 115.79 × 69.60
  4. Step 4: Simplify right side
    77.64x = 8,058.98
  5. Step 5: Solve for x
    x = 8,058.98/77.64
  6. Step 6: Final answer
    x = 103.80

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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.