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Finding the Fourth Proportional to 189.80, 284.58 and 81.74

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Solution

The fourth proportional to 189.80, 284.58 and 81.74 is: 122.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    189.80 : 284.58 = 81.74 : x
  2. Step 2: Convert to fraction form
    189.80/284.58 = 81.74/x
  3. Step 3: Cross multiply
    189.80x = 284.58 × 81.74
  4. Step 4: Simplify right side
    189.80x = 23,261.57
  5. Step 5: Solve for x
    x = 23,261.57/189.80
  6. Step 6: Final answer
    x = 122.56

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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.