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Finding the Fourth Proportional to 105.38, 157.99 and 85.80

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Solution

The fourth proportional to 105.38, 157.99 and 85.80 is: 128.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.38 : 157.99 = 85.80 : x
  2. Step 2: Convert to fraction form
    105.38/157.99 = 85.80/x
  3. Step 3: Cross multiply
    105.38x = 157.99 × 85.80
  4. Step 4: Simplify right side
    105.38x = 13,555.54
  5. Step 5: Solve for x
    x = 13,555.54/105.38
  6. Step 6: Final answer
    x = 128.63

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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.