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Finding the Fourth Proportional to 77.74, 107.21 and 49.71

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Solution

The fourth proportional to 77.74, 107.21 and 49.71 is: 68.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.74 : 107.21 = 49.71 : x
  2. Step 2: Convert to fraction form
    77.74/107.21 = 49.71/x
  3. Step 3: Cross multiply
    77.74x = 107.21 × 49.71
  4. Step 4: Simplify right side
    77.74x = 5,329.41
  5. Step 5: Solve for x
    x = 5,329.41/77.74
  6. Step 6: Final answer
    x = 68.55

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.