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Finding the Fourth Proportional to 80.99, 121.62 and 72.18

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Solution

The fourth proportional to 80.99, 121.62 and 72.18 is: 108.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.99 : 121.62 = 72.18 : x
  2. Step 2: Convert to fraction form
    80.99/121.62 = 72.18/x
  3. Step 3: Cross multiply
    80.99x = 121.62 × 72.18
  4. Step 4: Simplify right side
    80.99x = 8,778.53
  5. Step 5: Solve for x
    x = 8,778.53/80.99
  6. Step 6: Final answer
    x = 108.40

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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.