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Finding the Fourth Proportional to 121.62, 181.96 and 90.71

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Solution

The fourth proportional to 121.62, 181.96 and 90.71 is: 135.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.62 : 181.96 = 90.71 : x
  2. Step 2: Convert to fraction form
    121.62/181.96 = 90.71/x
  3. Step 3: Cross multiply
    121.62x = 181.96 × 90.71
  4. Step 4: Simplify right side
    121.62x = 16,505.59
  5. Step 5: Solve for x
    x = 16,505.59/121.62
  6. Step 6: Final answer
    x = 135.71

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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.