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Finding the Fourth Proportional to 8.57, 11.81 and 7.80

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Solution

The fourth proportional to 8.57, 11.81 and 7.80 is: 10.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    8.57 : 11.81 = 7.80 : x
  2. Step 2: Convert to fraction form
    8.57/11.81 = 7.80/x
  3. Step 3: Cross multiply
    8.57x = 11.81 × 7.80
  4. Step 4: Simplify right side
    8.57x = 92.08
  5. Step 5: Solve for x
    x = 92.08/8.57
  6. Step 6: Final answer
    x = 10.75

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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.