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Finding the Fourth Proportional to 121.85, 183.15 and 81.53

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Solution

The fourth proportional to 121.85, 183.15 and 81.53 is: 122.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.85 : 183.15 = 81.53 : x
  2. Step 2: Convert to fraction form
    121.85/183.15 = 81.53/x
  3. Step 3: Cross multiply
    121.85x = 183.15 × 81.53
  4. Step 4: Simplify right side
    121.85x = 14,931.99
  5. Step 5: Solve for x
    x = 14,931.99/121.85
  6. Step 6: Final answer
    x = 122.55

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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.