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Finding the Fourth Proportional to 86.79, 119.70 and 75.87

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Solution

The fourth proportional to 86.79, 119.70 and 75.87 is: 104.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.79 : 119.70 = 75.87 : x
  2. Step 2: Convert to fraction form
    86.79/119.70 = 75.87/x
  3. Step 3: Cross multiply
    86.79x = 119.70 × 75.87
  4. Step 4: Simplify right side
    86.79x = 9,081.64
  5. Step 5: Solve for x
    x = 9,081.64/86.79
  6. Step 6: Final answer
    x = 104.64

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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.