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Finding the Fourth Proportional to 86.81, 119.82 and 55.74

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Solution

The fourth proportional to 86.81, 119.82 and 55.74 is: 76.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.81 : 119.82 = 55.74 : x
  2. Step 2: Convert to fraction form
    86.81/119.82 = 55.74/x
  3. Step 3: Cross multiply
    86.81x = 119.82 × 55.74
  4. Step 4: Simplify right side
    86.81x = 6,679.43
  5. Step 5: Solve for x
    x = 6,679.43/86.81
  6. Step 6: Final answer
    x = 76.95

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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.