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Finding the Fourth Proportional to 77.81, 107.45 and 64.68

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Solution

The fourth proportional to 77.81, 107.45 and 64.68 is: 89.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.81 : 107.45 = 64.68 : x
  2. Step 2: Convert to fraction form
    77.81/107.45 = 64.68/x
  3. Step 3: Cross multiply
    77.81x = 107.45 × 64.68
  4. Step 4: Simplify right side
    77.81x = 6,949.54
  5. Step 5: Solve for x
    x = 6,949.54/77.81
  6. Step 6: Final answer
    x = 89.32

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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.