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Finding the Fourth Proportional to 139, 191.82 and 87.28

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Solution

The fourth proportional to 139, 191.82 and 87.28 is: 120.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    139 : 191.82 = 87.28 : x
  2. Step 2: Convert to fraction form
    139/191.82 = 87.28/x
  3. Step 3: Cross multiply
    139x = 191.82 × 87.28
  4. Step 4: Simplify right side
    139x = 16,742.05
  5. Step 5: Solve for x
    x = 16,742.05/139
  6. Step 6: Final answer
    x = 120.45

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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.