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Finding the Fourth Proportional to 77.79, 115.82 and 74.31

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Solution

The fourth proportional to 77.79, 115.82 and 74.31 is: 110.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.79 : 115.82 = 74.31 : x
  2. Step 2: Convert to fraction form
    77.79/115.82 = 74.31/x
  3. Step 3: Cross multiply
    77.79x = 115.82 × 74.31
  4. Step 4: Simplify right side
    77.79x = 8,606.21
  5. Step 5: Solve for x
    x = 8,606.21/77.79
  6. Step 6: Final answer
    x = 110.63

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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.