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Finding the Fourth Proportional to 105.96, 145.86 and 76.80

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Solution

The fourth proportional to 105.96, 145.86 and 76.80 is: 105.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.96 : 145.86 = 76.80 : x
  2. Step 2: Convert to fraction form
    105.96/145.86 = 76.80/x
  3. Step 3: Cross multiply
    105.96x = 145.86 × 76.80
  4. Step 4: Simplify right side
    105.96x = 11,202.05
  5. Step 5: Solve for x
    x = 11,202.05/105.96
  6. Step 6: Final answer
    x = 105.72

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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.