Given points are \( A(1, -2) \), \( B(a, 6) \), and \( C\left(\frac{3}{2}, -2\right) \).
- The circumcenter \( O \) is \( \left(\frac{5}{3}, 4\right) \).
Calculate \( AO \) and \( BO \) (Using Distance Formula): - \( AO = BO \):
\((a - 5)^2 + \left(\frac{a}{4} + 2\right)^2 = (a - 5)^2 + \left(\frac{a}{4} - 6\right)^2\)
Solving this gives \( a = 8 \).
Determine Side Lengths of the Triangle: - With \( a = 8 \): \( AB = 8 \), \( AC = 6 \), \( BC = 10 \).
Calculate Circumradius (\( \alpha \)), Area (\( \beta \)), and Perimeter (\( \gamma \)): - Circumradius \( \alpha = 5 \), Area \( \beta = 24 \), Perimeter \( \gamma = 24 \)
Compute \( \alpha + \beta + \gamma \):
\(\alpha + \beta + \gamma = 5 + 24 + 24 = 53\)
So, the correct option is: \( \mathbf{53} \)