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Finding the Fourth Proportional to 77.50, 116.25 and 20.50

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Solution

The fourth proportional to 77.50, 116.25 and 20.50 is: 30.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.50 : 116.25 = 20.50 : x
  2. Step 2: Convert to fraction form
    77.50/116.25 = 20.50/x
  3. Step 3: Cross multiply
    77.50x = 116.25 × 20.50
  4. Step 4: Simplify right side
    77.50x = 2,383.13
  5. Step 5: Solve for x
    x = 2,383.13/77.50
  6. Step 6: Final answer
    x = 30.75

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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.