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Finding the Fourth Proportional to 80.65, 111.17 and 70.85

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Solution

The fourth proportional to 80.65, 111.17 and 70.85 is: 97.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.65 : 111.17 = 70.85 : x
  2. Step 2: Convert to fraction form
    80.65/111.17 = 70.85/x
  3. Step 3: Cross multiply
    80.65x = 111.17 × 70.85
  4. Step 4: Simplify right side
    80.65x = 7,876.54
  5. Step 5: Solve for x
    x = 7,876.54/80.65
  6. Step 6: Final answer
    x = 97.67

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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.