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Finding the Fourth Proportional to 76.75, 105.84 and 65.12

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Solution

The fourth proportional to 76.75, 105.84 and 65.12 is: 89.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.75 : 105.84 = 65.12 : x
  2. Step 2: Convert to fraction form
    76.75/105.84 = 65.12/x
  3. Step 3: Cross multiply
    76.75x = 105.84 × 65.12
  4. Step 4: Simplify right side
    76.75x = 6,891.45
  5. Step 5: Solve for x
    x = 6,891.45/76.75
  6. Step 6: Final answer
    x = 89.80

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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.