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Finding the Fourth Proportional to 120.80, 166.80 and 84

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Solution

The fourth proportional to 120.80, 166.80 and 84 is: 115.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.80 : 166.80 = 84 : x
  2. Step 2: Convert to fraction form
    120.80/166.80 = 84/x
  3. Step 3: Cross multiply
    120.80x = 166.80 × 84
  4. Step 4: Simplify right side
    120.80x = 14,011.20
  5. Step 5: Solve for x
    x = 14,011.20/120.80
  6. Step 6: Final answer
    x = 115.99

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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.