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Finding the Fourth Proportional to 189.96, 261.78 and 138.12

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Solution

The fourth proportional to 189.96, 261.78 and 138.12 is: 190.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    189.96 : 261.78 = 138.12 : x
  2. Step 2: Convert to fraction form
    189.96/261.78 = 138.12/x
  3. Step 3: Cross multiply
    189.96x = 261.78 × 138.12
  4. Step 4: Simplify right side
    189.96x = 36,157.05
  5. Step 5: Solve for x
    x = 36,157.05/189.96
  6. Step 6: Final answer
    x = 190.34

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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.