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Finding the Fourth Proportional to 85.13, 128.34 and 79.25

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Solution

The fourth proportional to 85.13, 128.34 and 79.25 is: 119.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.13 : 128.34 = 79.25 : x
  2. Step 2: Convert to fraction form
    85.13/128.34 = 79.25/x
  3. Step 3: Cross multiply
    85.13x = 128.34 × 79.25
  4. Step 4: Simplify right side
    85.13x = 10,170.95
  5. Step 5: Solve for x
    x = 10,170.95/85.13
  6. Step 6: Final answer
    x = 119.48

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.