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Finding the Fourth Proportional to 121.08, 181.42 and 66.81

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Solution

The fourth proportional to 121.08, 181.42 and 66.81 is: 100.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.08 : 181.42 = 66.81 : x
  2. Step 2: Convert to fraction form
    121.08/181.42 = 66.81/x
  3. Step 3: Cross multiply
    121.08x = 181.42 × 66.81
  4. Step 4: Simplify right side
    121.08x = 12,120.67
  5. Step 5: Solve for x
    x = 12,120.67/121.08
  6. Step 6: Final answer
    x = 100.10

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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.