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Finding the Fourth Proportional to 77.72, 107.28 and 65.44

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Solution

The fourth proportional to 77.72, 107.28 and 65.44 is: 90.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.72 : 107.28 = 65.44 : x
  2. Step 2: Convert to fraction form
    77.72/107.28 = 65.44/x
  3. Step 3: Cross multiply
    77.72x = 107.28 × 65.44
  4. Step 4: Simplify right side
    77.72x = 7,020.40
  5. Step 5: Solve for x
    x = 7,020.40/77.72
  6. Step 6: Final answer
    x = 90.33

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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.