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Finding the Fourth Proportional to 216.40, 298.62 and 121.87

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Solution

The fourth proportional to 216.40, 298.62 and 121.87 is: 168.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.40 : 298.62 = 121.87 : x
  2. Step 2: Convert to fraction form
    216.40/298.62 = 121.87/x
  3. Step 3: Cross multiply
    216.40x = 298.62 × 121.87
  4. Step 4: Simplify right side
    216.40x = 36,392.82
  5. Step 5: Solve for x
    x = 36,392.82/216.40
  6. Step 6: Final answer
    x = 168.17

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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.