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Finding the Fourth Proportional to 77.15, 115.76 and 38.64

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Solution

The fourth proportional to 77.15, 115.76 and 38.64 is: 57.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.15 : 115.76 = 38.64 : x
  2. Step 2: Convert to fraction form
    77.15/115.76 = 38.64/x
  3. Step 3: Cross multiply
    77.15x = 115.76 × 38.64
  4. Step 4: Simplify right side
    77.15x = 4,472.77
  5. Step 5: Solve for x
    x = 4,472.77/77.15
  6. Step 6: Final answer
    x = 57.98

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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.