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Finding the Fourth Proportional to 11.50, 15.87 and 7.86

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Solution

The fourth proportional to 11.50, 15.87 and 7.86 is: 10.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    11.50 : 15.87 = 7.86 : x
  2. Step 2: Convert to fraction form
    11.50/15.87 = 7.86/x
  3. Step 3: Cross multiply
    11.50x = 15.87 × 7.86
  4. Step 4: Simplify right side
    11.50x = 124.81
  5. Step 5: Solve for x
    x = 124.81/11.50
  6. Step 6: Final answer
    x = 10.86

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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.