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Finding the Fourth Proportional to 86.36, 118.94 and 71.78

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Solution

The fourth proportional to 86.36, 118.94 and 71.78 is: 98.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.36 : 118.94 = 71.78 : x
  2. Step 2: Convert to fraction form
    86.36/118.94 = 71.78/x
  3. Step 3: Cross multiply
    86.36x = 118.94 × 71.78
  4. Step 4: Simplify right side
    86.36x = 8,536.56
  5. Step 5: Solve for x
    x = 8,536.56/86.36
  6. Step 6: Final answer
    x = 98.85

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.