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Finding the Fourth Proportional to 80.81, 121.21 and 19.94

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Solution

The fourth proportional to 80.81, 121.21 and 19.94 is: 29.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.81 : 121.21 = 19.94 : x
  2. Step 2: Convert to fraction form
    80.81/121.21 = 19.94/x
  3. Step 3: Cross multiply
    80.81x = 121.21 × 19.94
  4. Step 4: Simplify right side
    80.81x = 2,417.24
  5. Step 5: Solve for x
    x = 2,417.24/80.81
  6. Step 6: Final answer
    x = 29.91

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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.