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Finding the Fourth Proportional to 189.96, 285.39 and 129.21

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Solution

The fourth proportional to 189.96, 285.39 and 129.21 is: 194.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    189.96 : 285.39 = 129.21 : x
  2. Step 2: Convert to fraction form
    189.96/285.39 = 129.21/x
  3. Step 3: Cross multiply
    189.96x = 285.39 × 129.21
  4. Step 4: Simplify right side
    189.96x = 36,875.24
  5. Step 5: Solve for x
    x = 36,875.24/189.96
  6. Step 6: Final answer
    x = 194.12

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.