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Finding the Fourth Proportional to 139.08, 191.79 and 117.21

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Solution

The fourth proportional to 139.08, 191.79 and 117.21 is: 161.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.08 : 191.79 = 117.21 : x
  2. Step 2: Convert to fraction form
    139.08/191.79 = 117.21/x
  3. Step 3: Cross multiply
    139.08x = 191.79 × 117.21
  4. Step 4: Simplify right side
    139.08x = 22,479.71
  5. Step 5: Solve for x
    x = 22,479.71/139.08
  6. Step 6: Final answer
    x = 161.63

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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.