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Finding the Fourth Proportional to 121.29, 181.78 and 72.56

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Solution

The fourth proportional to 121.29, 181.78 and 72.56 is: 108.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.29 : 181.78 = 72.56 : x
  2. Step 2: Convert to fraction form
    121.29/181.78 = 72.56/x
  3. Step 3: Cross multiply
    121.29x = 181.78 × 72.56
  4. Step 4: Simplify right side
    121.29x = 13,189.62
  5. Step 5: Solve for x
    x = 13,189.62/121.29
  6. Step 6: Final answer
    x = 108.75

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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.