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Finding the Fourth Proportional to 121.16, 166.90 and 86.60

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Solution

The fourth proportional to 121.16, 166.90 and 86.60 is: 119.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.16 : 166.90 = 86.60 : x
  2. Step 2: Convert to fraction form
    121.16/166.90 = 86.60/x
  3. Step 3: Cross multiply
    121.16x = 166.90 × 86.60
  4. Step 4: Simplify right side
    121.16x = 14,453.54
  5. Step 5: Solve for x
    x = 14,453.54/121.16
  6. Step 6: Final answer
    x = 119.29

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.