Problem: The sides of a triangle are 25,39, and 40. The diameter of the circumscribed circle is:
Answer Choices:
A. 133/3
B. 125/3
C. 42
D. 41
E. 40
Solution:
Let h be the altitude to side 39. Then 252R=h40
But 21h⋅39= Area =B(s−a)(s−b)(s−c)
∴h=39252⋅13⋅12⋅27=24 ∴ 2R=3125