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Finding the Fourth Proportional to 190.78, 263.40 and 138.49

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Solution

The fourth proportional to 190.78, 263.40 and 138.49 is: 191.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    190.78 : 263.40 = 138.49 : x
  2. Step 2: Convert to fraction form
    190.78/263.40 = 138.49/x
  3. Step 3: Cross multiply
    190.78x = 263.40 × 138.49
  4. Step 4: Simplify right side
    190.78x = 36,478.27
  5. Step 5: Solve for x
    x = 36,478.27/190.78
  6. Step 6: Final answer
    x = 191.21

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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.