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Finding the Fourth Proportional to 128.16, 191.68 and 108.76

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Solution

The fourth proportional to 128.16, 191.68 and 108.76 is: 162.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.16 : 191.68 = 108.76 : x
  2. Step 2: Convert to fraction form
    128.16/191.68 = 108.76/x
  3. Step 3: Cross multiply
    128.16x = 191.68 × 108.76
  4. Step 4: Simplify right side
    128.16x = 20,847.12
  5. Step 5: Solve for x
    x = 20,847.12/128.16
  6. Step 6: Final answer
    x = 162.66

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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.