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Finding the Fourth Proportional to 78.33, 107.81 and 66.65

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Solution

The fourth proportional to 78.33, 107.81 and 66.65 is: 91.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.33 : 107.81 = 66.65 : x
  2. Step 2: Convert to fraction form
    78.33/107.81 = 66.65/x
  3. Step 3: Cross multiply
    78.33x = 107.81 × 66.65
  4. Step 4: Simplify right side
    78.33x = 7,185.54
  5. Step 5: Solve for x
    x = 7,185.54/78.33
  6. Step 6: Final answer
    x = 91.73

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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.