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Finding the Fourth Proportional to 85.99, 128.36 and 79.97

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Solution

The fourth proportional to 85.99, 128.36 and 79.97 is: 119.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.99 : 128.36 = 79.97 : x
  2. Step 2: Convert to fraction form
    85.99/128.36 = 79.97/x
  3. Step 3: Cross multiply
    85.99x = 128.36 × 79.97
  4. Step 4: Simplify right side
    85.99x = 10,264.87
  5. Step 5: Solve for x
    x = 10,264.87/85.99
  6. Step 6: Final answer
    x = 119.37

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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.