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Finding the Fourth Proportional to 189.42, 284.20 and 81.18

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Solution

The fourth proportional to 189.42, 284.20 and 81.18 is: 121.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    189.42 : 284.20 = 81.18 : x
  2. Step 2: Convert to fraction form
    189.42/284.20 = 81.18/x
  3. Step 3: Cross multiply
    189.42x = 284.20 × 81.18
  4. Step 4: Simplify right side
    189.42x = 23,071.36
  5. Step 5: Solve for x
    x = 23,071.36/189.42
  6. Step 6: Final answer
    x = 121.80

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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.