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Finding the Fourth Proportional to 77.94, 107.40 and 57.21

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Solution

The fourth proportional to 77.94, 107.40 and 57.21 is: 78.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.94 : 107.40 = 57.21 : x
  2. Step 2: Convert to fraction form
    77.94/107.40 = 57.21/x
  3. Step 3: Cross multiply
    77.94x = 107.40 × 57.21
  4. Step 4: Simplify right side
    77.94x = 6,144.35
  5. Step 5: Solve for x
    x = 6,144.35/77.94
  6. Step 6: Final answer
    x = 78.83

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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.