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Finding the Fourth Proportional to 78.44, 107.61 and 76.80

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Solution

The fourth proportional to 78.44, 107.61 and 76.80 is: 105.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.44 : 107.61 = 76.80 : x
  2. Step 2: Convert to fraction form
    78.44/107.61 = 76.80/x
  3. Step 3: Cross multiply
    78.44x = 107.61 × 76.80
  4. Step 4: Simplify right side
    78.44x = 8,264.45
  5. Step 5: Solve for x
    x = 8,264.45/78.44
  6. Step 6: Final answer
    x = 105.36

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.