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Finding the Fourth Proportional to 128.68, 192.68 and 105.60

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Solution

The fourth proportional to 128.68, 192.68 and 105.60 is: 158.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.68 : 192.68 = 105.60 : x
  2. Step 2: Convert to fraction form
    128.68/192.68 = 105.60/x
  3. Step 3: Cross multiply
    128.68x = 192.68 × 105.60
  4. Step 4: Simplify right side
    128.68x = 20,347.01
  5. Step 5: Solve for x
    x = 20,347.01/128.68
  6. Step 6: Final answer
    x = 158.12

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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.