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Finding the Fourth Proportional to 77.34, 115.45 and 74.78

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Solution

The fourth proportional to 77.34, 115.45 and 74.78 is: 111.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.34 : 115.45 = 74.78 : x
  2. Step 2: Convert to fraction form
    77.34/115.45 = 74.78/x
  3. Step 3: Cross multiply
    77.34x = 115.45 × 74.78
  4. Step 4: Simplify right side
    77.34x = 8,633.35
  5. Step 5: Solve for x
    x = 8,633.35/77.34
  6. Step 6: Final answer
    x = 111.63

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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.