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Finding the Fourth Proportional to 121.57, 167.81 and 86.77

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Solution

The fourth proportional to 121.57, 167.81 and 86.77 is: 119.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.57 : 167.81 = 86.77 : x
  2. Step 2: Convert to fraction form
    121.57/167.81 = 86.77/x
  3. Step 3: Cross multiply
    121.57x = 167.81 × 86.77
  4. Step 4: Simplify right side
    121.57x = 14,560.65
  5. Step 5: Solve for x
    x = 14,560.65/121.57
  6. Step 6: Final answer
    x = 119.77

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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.