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Finding the Fourth Proportional to 218.78, 326.43 and 191.78

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Solution

The fourth proportional to 218.78, 326.43 and 191.78 is: 286.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    218.78 : 326.43 = 191.78 : x
  2. Step 2: Convert to fraction form
    218.78/326.43 = 191.78/x
  3. Step 3: Cross multiply
    218.78x = 326.43 × 191.78
  4. Step 4: Simplify right side
    218.78x = 62,601.79
  5. Step 5: Solve for x
    x = 62,601.79/218.78
  6. Step 6: Final answer
    x = 286.14

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.