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Finding the Third Proportional to 39.79 and 86.80

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Solution

The third proportional to 39.79 and 86.80 is: 189.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    39.79 : 86.80 = 86.80 : x
  2. Step 2: Convert to fraction form
    39.79/86.80 = 86.80/x
  3. Step 3: Cross multiply
    39.79x = 86.80 × 86.80
  4. Step 4: Simplify right side
    39.79x = 7,533.87
  5. Step 5: Solve for x
    x = 7,533.87/39.79
  6. Step 6: Final answer
    x = 189.32

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Why These Related Problems?

These problems maintain the same ratio (2.18) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.