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Finding the Fourth Proportional to 91.70, 126.18 and 78.33

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Solution

The fourth proportional to 91.70, 126.18 and 78.33 is: 107.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.70 : 126.18 = 78.33 : x
  2. Step 2: Convert to fraction form
    91.70/126.18 = 78.33/x
  3. Step 3: Cross multiply
    91.70x = 126.18 × 78.33
  4. Step 4: Simplify right side
    91.70x = 9,883.68
  5. Step 5: Solve for x
    x = 9,883.68/91.70
  6. Step 6: Final answer
    x = 107.79

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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.