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Finding the Fourth Proportional to 76.15, 105.79 and 75.40

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Solution

The fourth proportional to 76.15, 105.79 and 75.40 is: 104.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.15 : 105.79 = 75.40 : x
  2. Step 2: Convert to fraction form
    76.15/105.79 = 75.40/x
  3. Step 3: Cross multiply
    76.15x = 105.79 × 75.40
  4. Step 4: Simplify right side
    76.15x = 7,976.57
  5. Step 5: Solve for x
    x = 7,976.57/76.15
  6. Step 6: Final answer
    x = 104.75

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.