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Finding the Fourth Proportional to 189.68, 284.35 and 81.40

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Solution

The fourth proportional to 189.68, 284.35 and 81.40 is: 122.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    189.68 : 284.35 = 81.40 : x
  2. Step 2: Convert to fraction form
    189.68/284.35 = 81.40/x
  3. Step 3: Cross multiply
    189.68x = 284.35 × 81.40
  4. Step 4: Simplify right side
    189.68x = 23,146.09
  5. Step 5: Solve for x
    x = 23,146.09/189.68
  6. Step 6: Final answer
    x = 122.03

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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.