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Finding the Fourth Proportional to 111.30, 166.65 and 80.70

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Solution

The fourth proportional to 111.30, 166.65 and 80.70 is: 120.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    111.30 : 166.65 = 80.70 : x
  2. Step 2: Convert to fraction form
    111.30/166.65 = 80.70/x
  3. Step 3: Cross multiply
    111.30x = 166.65 × 80.70
  4. Step 4: Simplify right side
    111.30x = 13,448.66
  5. Step 5: Solve for x
    x = 13,448.66/111.30
  6. Step 6: Final answer
    x = 120.83

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.