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Finding the Fourth Proportional to 128.45, 192.69 and 77.08

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Solution

The fourth proportional to 128.45, 192.69 and 77.08 is: 115.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.45 : 192.69 = 77.08 : x
  2. Step 2: Convert to fraction form
    128.45/192.69 = 77.08/x
  3. Step 3: Cross multiply
    128.45x = 192.69 × 77.08
  4. Step 4: Simplify right side
    128.45x = 14,852.55
  5. Step 5: Solve for x
    x = 14,852.55/128.45
  6. Step 6: Final answer
    x = 115.63

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.