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Finding the Fourth Proportional to 81.02, 111.69 and 77.99

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Solution

The fourth proportional to 81.02, 111.69 and 77.99 is: 107.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.02 : 111.69 = 77.99 : x
  2. Step 2: Convert to fraction form
    81.02/111.69 = 77.99/x
  3. Step 3: Cross multiply
    81.02x = 111.69 × 77.99
  4. Step 4: Simplify right side
    81.02x = 8,710.14
  5. Step 5: Solve for x
    x = 8,710.14/81.02
  6. Step 6: Final answer
    x = 107.50

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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.