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Finding the Fourth Proportional to 121.50, 181.85 and 90.99

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Solution

The fourth proportional to 121.50, 181.85 and 90.99 is: 136.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.50 : 181.85 = 90.99 : x
  2. Step 2: Convert to fraction form
    121.50/181.85 = 90.99/x
  3. Step 3: Cross multiply
    121.50x = 181.85 × 90.99
  4. Step 4: Simplify right side
    121.50x = 16,546.08
  5. Step 5: Solve for x
    x = 16,546.08/121.50
  6. Step 6: Final answer
    x = 136.18

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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.