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Finding the Fourth Proportional to 77.90, 106.65 and 77.09

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Solution

The fourth proportional to 77.90, 106.65 and 77.09 is: 105.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.90 : 106.65 = 77.09 : x
  2. Step 2: Convert to fraction form
    77.90/106.65 = 77.09/x
  3. Step 3: Cross multiply
    77.90x = 106.65 × 77.09
  4. Step 4: Simplify right side
    77.90x = 8,221.12
  5. Step 5: Solve for x
    x = 8,221.12/77.90
  6. Step 6: Final answer
    x = 105.54

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.