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Finding the Fourth Proportional to 128.57, 191.79 and 114.66

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Solution

The fourth proportional to 128.57, 191.79 and 114.66 is: 171.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.57 : 191.79 = 114.66 : x
  2. Step 2: Convert to fraction form
    128.57/191.79 = 114.66/x
  3. Step 3: Cross multiply
    128.57x = 191.79 × 114.66
  4. Step 4: Simplify right side
    128.57x = 21,990.64
  5. Step 5: Solve for x
    x = 21,990.64/128.57
  6. Step 6: Final answer
    x = 171.05

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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.