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Finding the Fourth Proportional to 7.87, 10.90 and 7.77

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Solution

The fourth proportional to 7.87, 10.90 and 7.77 is: 10.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    7.87 : 10.90 = 7.77 : x
  2. Step 2: Convert to fraction form
    7.87/10.90 = 7.77/x
  3. Step 3: Cross multiply
    7.87x = 10.90 × 7.77
  4. Step 4: Simplify right side
    7.87x = 84.69
  5. Step 5: Solve for x
    x = 84.69/7.87
  6. Step 6: Final answer
    x = 10.76

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.