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Finding the Fourth Proportional to 190.80, 285.90 and 81.02

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Solution

The fourth proportional to 190.80, 285.90 and 81.02 is: 121.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    190.80 : 285.90 = 81.02 : x
  2. Step 2: Convert to fraction form
    190.80/285.90 = 81.02/x
  3. Step 3: Cross multiply
    190.80x = 285.90 × 81.02
  4. Step 4: Simplify right side
    190.80x = 23,163.62
  5. Step 5: Solve for x
    x = 23,163.62/190.80
  6. Step 6: Final answer
    x = 121.40

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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.