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Finding the Fourth Proportional to 128.98, 192.34 and 112.78

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Solution

The fourth proportional to 128.98, 192.34 and 112.78 is: 168.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.98 : 192.34 = 112.78 : x
  2. Step 2: Convert to fraction form
    128.98/192.34 = 112.78/x
  3. Step 3: Cross multiply
    128.98x = 192.34 × 112.78
  4. Step 4: Simplify right side
    128.98x = 21,692.11
  5. Step 5: Solve for x
    x = 21,692.11/128.98
  6. Step 6: Final answer
    x = 168.18

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.