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Finding the Fourth Proportional to 212.87, 318.49 and 121.61

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Solution

The fourth proportional to 212.87, 318.49 and 121.61 is: 181.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.87 : 318.49 = 121.61 : x
  2. Step 2: Convert to fraction form
    212.87/318.49 = 121.61/x
  3. Step 3: Cross multiply
    212.87x = 318.49 × 121.61
  4. Step 4: Simplify right side
    212.87x = 38,731.57
  5. Step 5: Solve for x
    x = 38,731.57/212.87
  6. Step 6: Final answer
    x = 181.95

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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.