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Finding the Fourth Proportional to 139.05, 191.70 and 99.61

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Solution

The fourth proportional to 139.05, 191.70 and 99.61 is: 137.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.05 : 191.70 = 99.61 : x
  2. Step 2: Convert to fraction form
    139.05/191.70 = 99.61/x
  3. Step 3: Cross multiply
    139.05x = 191.70 × 99.61
  4. Step 4: Simplify right side
    139.05x = 19,094.76
  5. Step 5: Solve for x
    x = 19,094.76/139.05
  6. Step 6: Final answer
    x = 137.32

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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.