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Finding the Fourth Proportional to 86.80, 120.33 and 85.12

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Solution

The fourth proportional to 86.80, 120.33 and 85.12 is: 118.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.80 : 120.33 = 85.12 : x
  2. Step 2: Convert to fraction form
    86.80/120.33 = 85.12/x
  3. Step 3: Cross multiply
    86.80x = 120.33 × 85.12
  4. Step 4: Simplify right side
    86.80x = 10,242.49
  5. Step 5: Solve for x
    x = 10,242.49/86.80
  6. Step 6: Final answer
    x = 118.00

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.