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Finding the Fourth Proportional to 121.16, 181.74 and 78.68

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Solution

The fourth proportional to 121.16, 181.74 and 78.68 is: 118.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.16 : 181.74 = 78.68 : x
  2. Step 2: Convert to fraction form
    121.16/181.74 = 78.68/x
  3. Step 3: Cross multiply
    121.16x = 181.74 × 78.68
  4. Step 4: Simplify right side
    121.16x = 14,299.30
  5. Step 5: Solve for x
    x = 14,299.30/121.16
  6. Step 6: Final answer
    x = 118.02

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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.