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Finding the Fourth Proportional to 10, 13.80 and 8.56

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Solution

The fourth proportional to 10, 13.80 and 8.56 is: 11.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    10 : 13.80 = 8.56 : x
  2. Step 2: Convert to fraction form
    10/13.80 = 8.56/x
  3. Step 3: Cross multiply
    10x = 13.80 × 8.56
  4. Step 4: Simplify right side
    10x = 118.13
  5. Step 5: Solve for x
    x = 118.13/10
  6. Step 6: Final answer
    x = 11.81

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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.