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Finding the Fourth Proportional to 139.78, 192.96 and 84.51

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Solution

The fourth proportional to 139.78, 192.96 and 84.51 is: 116.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.78 : 192.96 = 84.51 : x
  2. Step 2: Convert to fraction form
    139.78/192.96 = 84.51/x
  3. Step 3: Cross multiply
    139.78x = 192.96 × 84.51
  4. Step 4: Simplify right side
    139.78x = 16,305.66
  5. Step 5: Solve for x
    x = 16,305.66/139.78
  6. Step 6: Final answer
    x = 116.65

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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.