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Finding the Fourth Proportional to 138.40, 190.95 and 83.15

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Solution

The fourth proportional to 138.40, 190.95 and 83.15 is: 114.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.40 : 190.95 = 83.15 : x
  2. Step 2: Convert to fraction form
    138.40/190.95 = 83.15/x
  3. Step 3: Cross multiply
    138.40x = 190.95 × 83.15
  4. Step 4: Simplify right side
    138.40x = 15,877.49
  5. Step 5: Solve for x
    x = 15,877.49/138.40
  6. Step 6: Final answer
    x = 114.72

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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.