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Finding the Fourth Proportional to 77.99, 117.21 and 51.11

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Solution

The fourth proportional to 77.99, 117.21 and 51.11 is: 76.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.99 : 117.21 = 51.11 : x
  2. Step 2: Convert to fraction form
    77.99/117.21 = 51.11/x
  3. Step 3: Cross multiply
    77.99x = 117.21 × 51.11
  4. Step 4: Simplify right side
    77.99x = 5,990.02
  5. Step 5: Solve for x
    x = 5,990.02/77.99
  6. Step 6: Final answer
    x = 76.81

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.