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Finding the Fourth Proportional to 138.15, 190.35 and 105.30

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Solution

The fourth proportional to 138.15, 190.35 and 105.30 is: 145.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.15 : 190.35 = 105.30 : x
  2. Step 2: Convert to fraction form
    138.15/190.35 = 105.30/x
  3. Step 3: Cross multiply
    138.15x = 190.35 × 105.30
  4. Step 4: Simplify right side
    138.15x = 20,043.86
  5. Step 5: Solve for x
    x = 20,043.86/138.15
  6. Step 6: Final answer
    x = 145.09

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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.