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Finding the Fourth Proportional to 91.70, 126.61 and 81.85

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Solution

The fourth proportional to 91.70, 126.61 and 81.85 is: 113.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.70 : 126.61 = 81.85 : x
  2. Step 2: Convert to fraction form
    91.70/126.61 = 81.85/x
  3. Step 3: Cross multiply
    91.70x = 126.61 × 81.85
  4. Step 4: Simplify right side
    91.70x = 10,363.41
  5. Step 5: Solve for x
    x = 10,363.41/91.70
  6. Step 6: Final answer
    x = 113.01

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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.