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Finding the Fourth Proportional to 121.13, 181.32 and 90.61

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Solution

The fourth proportional to 121.13, 181.32 and 90.61 is: 135.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.13 : 181.32 = 90.61 : x
  2. Step 2: Convert to fraction form
    121.13/181.32 = 90.61/x
  3. Step 3: Cross multiply
    121.13x = 181.32 × 90.61
  4. Step 4: Simplify right side
    121.13x = 16,429.41
  5. Step 5: Solve for x
    x = 16,429.41/121.13
  6. Step 6: Final answer
    x = 135.63

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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.