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Finding the Fourth Proportional to 189.20, 261.21 and 123.81

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Solution

The fourth proportional to 189.20, 261.21 and 123.81 is: 170.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    189.20 : 261.21 = 123.81 : x
  2. Step 2: Convert to fraction form
    189.20/261.21 = 123.81/x
  3. Step 3: Cross multiply
    189.20x = 261.21 × 123.81
  4. Step 4: Simplify right side
    189.20x = 32,340.41
  5. Step 5: Solve for x
    x = 32,340.41/189.20
  6. Step 6: Final answer
    x = 170.94

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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.