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Finding the Fourth Proportional to 128.61, 191.98 and 112.41

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Solution

The fourth proportional to 128.61, 191.98 and 112.41 is: 167.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.61 : 191.98 = 112.41 : x
  2. Step 2: Convert to fraction form
    128.61/191.98 = 112.41/x
  3. Step 3: Cross multiply
    128.61x = 191.98 × 112.41
  4. Step 4: Simplify right side
    128.61x = 21,580.19
  5. Step 5: Solve for x
    x = 21,580.19/128.61
  6. Step 6: Final answer
    x = 167.80

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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.