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Finding the Fourth Proportional to 80.90, 121.21 and 55.18

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Solution

The fourth proportional to 80.90, 121.21 and 55.18 is: 82.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.90 : 121.21 = 55.18 : x
  2. Step 2: Convert to fraction form
    80.90/121.21 = 55.18/x
  3. Step 3: Cross multiply
    80.90x = 121.21 × 55.18
  4. Step 4: Simplify right side
    80.90x = 6,687.93
  5. Step 5: Solve for x
    x = 6,687.93/80.90
  6. Step 6: Final answer
    x = 82.67

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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.