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Finding the Fourth Proportional to 77.75, 116.63 and 20.75

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Solution

The fourth proportional to 77.75, 116.63 and 20.75 is: 31.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.75 : 116.63 = 20.75 : x
  2. Step 2: Convert to fraction form
    77.75/116.63 = 20.75/x
  3. Step 3: Cross multiply
    77.75x = 116.63 × 20.75
  4. Step 4: Simplify right side
    77.75x = 2,419.97
  5. Step 5: Solve for x
    x = 2,419.97/77.75
  6. Step 6: Final answer
    x = 31.13

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.