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Finding the Fourth Proportional to 128.79, 192.58 and 108.74

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Solution

The fourth proportional to 128.79, 192.58 and 108.74 is: 162.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.79 : 192.58 = 108.74 : x
  2. Step 2: Convert to fraction form
    128.79/192.58 = 108.74/x
  3. Step 3: Cross multiply
    128.79x = 192.58 × 108.74
  4. Step 4: Simplify right side
    128.79x = 20,941.36
  5. Step 5: Solve for x
    x = 20,941.36/128.79
  6. Step 6: Final answer
    x = 162.60

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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.