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Finding the Fourth Proportional to 80.55, 120.72 and 66.99

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Solution

The fourth proportional to 80.55, 120.72 and 66.99 is: 100.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.55 : 120.72 = 66.99 : x
  2. Step 2: Convert to fraction form
    80.55/120.72 = 66.99/x
  3. Step 3: Cross multiply
    80.55x = 120.72 × 66.99
  4. Step 4: Simplify right side
    80.55x = 8,087.03
  5. Step 5: Solve for x
    x = 8,087.03/80.55
  6. Step 6: Final answer
    x = 100.40

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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.